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* KVM: x86: update %rip after emulating IOSean Christopherson2019-04-031-10/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 45def77ebf79e2e8942b89ed79294d97ce914fa0 upstream. Most (all?) x86 platforms provide a port IO based reset mechanism, e.g. OUT 92h or CF9h. Userspace may emulate said mechanism, i.e. reset a vCPU in response to KVM_EXIT_IO, without explicitly announcing to KVM that it is doing a reset, e.g. Qemu jams vCPU state and resumes running. To avoid corruping %rip after such a reset, commit 0967b7bf1c22 ("KVM: Skip pio instruction when it is emulated, not executed") changed the behavior of PIO handlers, i.e. today's "fast" PIO handling to skip the instruction prior to exiting to userspace. Full emulation doesn't need such tricks becase re-emulating the instruction will naturally handle %rip being changed to point at the reset vector. Updating %rip prior to executing to userspace has several drawbacks: - Userspace sees the wrong %rip on the exit, e.g. if PIO emulation fails it will likely yell about the wrong address. - Single step exits to userspace for are effectively dropped as KVM_EXIT_DEBUG is overwritten with KVM_EXIT_IO. - Behavior of PIO emulation is different depending on whether it goes down the fast path or the slow path. Rather than skip the PIO instruction before exiting to userspace, snapshot the linear %rip and cancel PIO completion if the current value does not match the snapshot. For a 64-bit vCPU, i.e. the most common scenario, the snapshot and comparison has negligible overhead as VMCS.GUEST_RIP will be cached regardless, i.e. there is no extra VMREAD in this case. All other alternatives to snapshotting the linear %rip that don't rely on an explicit reset announcenment suffer from one corner case or another. For example, canceling PIO completion on any write to %rip fails if userspace does a save/restore of %rip, and attempting to avoid that issue by canceling PIO only if %rip changed then fails if PIO collides with the reset %rip. Attempting to zero in on the exact reset vector won't work for APs, which means adding more hooks such as the vCPU's MP_STATE, and so on and so forth. Checking for a linear %rip match technically suffers from corner cases, e.g. userspace could theoretically rewrite the underlying code page and expect a different instruction to execute, or the guest hardcodes a PIO reset at 0xfffffff0, but those are far, far outside of what can be considered normal operation. Fixes: 432baf60eee3 ("KVM: VMX: use kvm_fast_pio_in for handling IN I/O") Cc: <stable@vger.kernel.org> Reported-by: Jim Mattson <jmattson@google.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: x86: Emulate MSR_IA32_ARCH_CAPABILITIES on AMD hostsSean Christopherson2019-04-033-14/+12
| | | | | | | | | | | | | | | | | | | | | | | commit 0cf9135b773bf32fba9dd8e6699c1b331ee4b749 upstream. The CPUID flag ARCH_CAPABILITIES is unconditioinally exposed to host userspace for all x86 hosts, i.e. KVM advertises ARCH_CAPABILITIES regardless of hardware support under the pretense that KVM fully emulates MSR_IA32_ARCH_CAPABILITIES. Unfortunately, only VMX hosts handle accesses to MSR_IA32_ARCH_CAPABILITIES (despite KVM_GET_MSRS also reporting MSR_IA32_ARCH_CAPABILITIES for all hosts). Move the MSR_IA32_ARCH_CAPABILITIES handling to common x86 code so that it's emulated on AMD hosts. Fixes: 1eaafe91a0df4 ("kvm: x86: IA32_ARCH_CAPABILITIES is always supported") Cc: stable@vger.kernel.org Reported-by: Xiaoyao Li <xiaoyao.li@linux.intel.com> Cc: Jim Mattson <jmattson@google.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: nVMX: Check a single byte for VMCS "launched" in nested early checksSean Christopherson2019-03-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1ce072cbfd8dba46f117804850398e0b3040a541 upstream. Nested early checks does a manual comparison of a VMCS' launched status in its asm blob to execute the correct VM-Enter instruction, i.e. VMLAUNCH vs. VMRESUME. The launched flag is a bool, which is a typedef of _Bool. C99 does not define an exact size for _Bool, stating only that is must be large enough to hold '0' and '1'. Most, if not all, compilers use a single byte for _Bool, including gcc[1]. The use of 'cmpl' instead of 'cmpb' was not deliberate, but rather the result of a copy-paste as the asm blob was directly derived from the asm blob for vCPU-run. This has not caused any known problems, likely due to compilers aligning variables to 4-byte or 8-byte boundaries and KVM zeroing out struct vcpu_vmx during allocation. I.e. vCPU-run accesses "junk" data, it just happens to always be zero and so doesn't affect the result. [1] https://gcc.gnu.org/ml/gcc-patches/2000-10/msg01127.html Fixes: 52017608da33 ("KVM: nVMX: add option to perform early consistency checks via H/W") Cc: <stable@vger.kernel.org> Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: nVMX: Ignore limit checks on VMX instructions using flat segmentsSean Christopherson2019-03-231-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | commit 34333cc6c2cb021662fd32e24e618d1b86de95bf upstream. Regarding segments with a limit==0xffffffff, the SDM officially states: When the effective limit is FFFFFFFFH (4 GBytes), these accesses may or may not cause the indicated exceptions. Behavior is implementation-specific and may vary from one execution to another. In practice, all CPUs that support VMX ignore limit checks for "flat segments", i.e. an expand-up data or code segment with base=0 and limit=0xffffffff. This is subtly different than wrapping the effective address calculation based on the address size, as the flat segment behavior also applies to accesses that would wrap the 4g boundary, e.g. a 4-byte access starting at 0xffffffff will access linear addresses 0xffffffff, 0x0, 0x1 and 0x2. Fixes: f9eb4af67c9d ("KVM: nVMX: VMX instructions: add checks for #GP/#SS exceptions") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: nVMX: Apply addr size mask to effective address for VMX instructionsSean Christopherson2019-03-231-2/+23
| | | | | | | | | | | | | | | | | commit 8570f9e881e3fde98801bb3a47eef84dd934d405 upstream. The address size of an instruction affects the effective address, not the virtual/linear address. The final address may still be truncated, e.g. to 32-bits outside of long mode, but that happens irrespective of the address size, e.g. a 32-bit address size can yield a 64-bit virtual address when using FS/GS with a non-zero base. Fixes: 064aea774768 ("KVM: nVMX: Decoding memory operands of VMX instructions") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: nVMX: Sign extend displacements of VMX instr's mem operandsSean Christopherson2019-03-231-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 946c522b603f281195af1df91837a1d4d1eb3bc9 upstream. The VMCS.EXIT_QUALIFCATION field reports the displacements of memory operands for various instructions, including VMX instructions, as a naturally sized unsigned value, but masks the value by the addr size, e.g. given a ModRM encoded as -0x28(%ebp), the -0x28 displacement is reported as 0xffffffd8 for a 32-bit address size. Despite some weird wording regarding sign extension, the SDM explicitly states that bits beyond the instructions address size are undefined: In all cases, bits of this field beyond the instruction’s address size are undefined. Failure to sign extend the displacement results in KVM incorrectly treating a negative displacement as a large positive displacement when the address size of the VMX instruction is smaller than KVM's native size, e.g. a 32-bit address size on a 64-bit KVM. The very original decoding, added by commit 064aea774768 ("KVM: nVMX: Decoding memory operands of VMX instructions"), sort of modeled sign extension by truncating the final virtual/linear address for a 32-bit address size. I.e. it messed up the effective address but made it work by adjusting the final address. When segmentation checks were added, the truncation logic was kept as-is and no sign extension logic was introduced. In other words, it kept calculating the wrong effective address while mostly generating the correct virtual/linear address. As the effective address is what's used in the segment limit checks, this results in KVM incorreclty injecting #GP/#SS faults due to non-existent segment violations when a nested VMM uses negative displacements with an address size smaller than KVM's native address size. Using the -0x28(%ebp) example, an EBP value of 0x1000 will result in KVM using 0x100000fd8 as the effective address when checking for a segment limit violation. This causes a 100% failure rate when running a 32-bit KVM build as L1 on top of a 64-bit KVM L0. Fixes: f9eb4af67c9d ("KVM: nVMX: VMX instructions: add checks for #GP/#SS exceptions") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: x86/mmu: Do not cache MMIO accesses while memslots are in fluxSean Christopherson2019-03-231-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ddfd1730fd829743e41213e32ccc8b4aa6dc8325 upstream. When installing new memslots, KVM sets bit 0 of the generation number to indicate that an update is in-progress. Until the update is complete, there are no guarantees as to whether a vCPU will see the old or the new memslots. Explicity prevent caching MMIO accesses so as to avoid using an access cached from the old memslots after the new memslots have been installed. Note that it is unclear whether or not disabling caching during the update window is strictly necessary as there is no definitive documentation as to what ordering guarantees KVM provides with respect to updating memslots. That being said, the MMIO spte code does not allow reusing sptes created while an update is in-progress, and the associated documentation explicitly states: We do not want to use an MMIO sptes created with an odd generation number, ... If KVM is unlucky and creates an MMIO spte while the low bit is 1, the next access to the spte will always be a cache miss. At the very least, disabling the per-vCPU MMIO cache during updates will make its behavior consistent with the MMIO spte behavior and documentation. Fixes: 56f17dd3fbc4 ("kvm: x86: fix stale mmio cache bug") Cc: <stable@vger.kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: x86/mmu: Detect MMIO generation wrap in any address spaceSean Christopherson2019-03-231-2/+19
| | | | | | | | | | | | | | | | | | | commit e1359e2beb8b0a1188abc997273acbaedc8ee791 upstream. The check to detect a wrap of the MMIO generation explicitly looks for a generation number of zero. Now that unique memslots generation numbers are assigned to each address space, only address space 0 will get a generation number of exactly zero when wrapping. E.g. when address space 1 goes from 0x7fffe to 0x80002, the MMIO generation number will wrap to 0x2. Adjust the MMIO generation to strip the address space modifier prior to checking for a wrap. Fixes: 4bd518f1598d ("KVM: use separate generations for each address space") Cc: <stable@vger.kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: VMX: Zero out *all* general purpose registers after VM-ExitSean Christopherson2019-03-231-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | commit 0e0ab73c9a0243736bcd779b30b717e23ba9a56d upstream. ...except RSP, which is restored by hardware as part of VM-Exit. Paolo theorized that restoring registers from the stack after a VM-Exit in lieu of zeroing them could lead to speculative execution with the guest's values, e.g. if the stack accesses miss the L1 cache[1]. Zeroing XORs are dirt cheap, so just be ultra-paranoid. Note that the scratch register (currently RCX) used to save/restore the guest state is also zeroed as its host-defined value is loaded via the stack, just with a MOV instead of a POP. [1] https://patchwork.kernel.org/patch/10771539/#22441255 Fixes: 0cb5b30698fd ("kvm: vmx: Scrub hardware GPRs at VM-exit") Cc: <stable@vger.kernel.org> Cc: Jim Mattson <jmattson@google.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: VMX: Compare only a single byte for VMCS' "launched" in vCPU-runSean Christopherson2019-03-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 61c08aa9606d4e48a8a50639c956448a720174c3 upstream. The vCPU-run asm blob does a manual comparison of a VMCS' launched status to execute the correct VM-Enter instruction, i.e. VMLAUNCH vs. VMRESUME. The launched flag is a bool, which is a typedef of _Bool. C99 does not define an exact size for _Bool, stating only that is must be large enough to hold '0' and '1'. Most, if not all, compilers use a single byte for _Bool, including gcc[1]. Originally, 'launched' was of type 'int' and so the asm blob used 'cmpl' to check the launch status. When 'launched' was moved to be stored on a per-VMCS basis, struct vcpu_vmx's "temporary" __launched flag was added in order to avoid having to pass the current VMCS into the asm blob. The new '__launched' was defined as a 'bool' and not an 'int', but the 'cmp' instruction was not updated. This has not caused any known problems, likely due to compilers aligning variables to 4-byte or 8-byte boundaries and KVM zeroing out struct vcpu_vmx during allocation. I.e. vCPU-run accesses "junk" data, it just happens to always be zero and so doesn't affect the result. [1] https://gcc.gnu.org/ml/gcc-patches/2000-10/msg01127.html Fixes: d462b8192368 ("KVM: VMX: Keep list of loaded VMCSs, instead of vcpus") Cc: <stable@vger.kernel.org> Reviewed-by: Jim Mattson <jmattson@google.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: Call kvm_arch_memslots_updated() before updating memslotsSean Christopherson2019-03-232-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 152482580a1b0accb60676063a1ac57b2d12daf6 upstream. kvm_arch_memslots_updated() is at this point in time an x86-specific hook for handling MMIO generation wraparound. x86 stashes 19 bits of the memslots generation number in its MMIO sptes in order to avoid full page fault walks for repeat faults on emulated MMIO addresses. Because only 19 bits are used, wrapping the MMIO generation number is possible, if unlikely. kvm_arch_memslots_updated() alerts x86 that the generation has changed so that it can invalidate all MMIO sptes in case the effective MMIO generation has wrapped so as to avoid using a stale spte, e.g. a (very) old spte that was created with generation==0. Given that the purpose of kvm_arch_memslots_updated() is to prevent consuming stale entries, it needs to be called before the new generation is propagated to memslots. Invalidating the MMIO sptes after updating memslots means that there is a window where a vCPU could dereference the new memslots generation, e.g. 0, and incorrectly reuse an old MMIO spte that was created with (pre-wrap) generation==0. Fixes: e59dbe09f8e6 ("KVM: Introduce kvm_arch_memslots_updated()") Cc: <stable@vger.kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()"Ben Gardon2019-03-231-13/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 92da008fa21034c369cdb8ca2b629fe5c196826b upstream. This reverts commit 71883a62fcd6c70639fa12cda733378b4d997409. The above commit contains an optimization to kvm_zap_gfn_range which uses gfn-limited TLB flushes, if enabled. If using these limited flushes, kvm_zap_gfn_range passes lock_flush_tlb=false to slot_handle_level_range which creates a race when the function unlocks to call cond_resched. See an example of this race below: CPU 0 CPU 1 CPU 3 // zap_direct_gfn_range mmu_lock() // *ptep == pte_1 *ptep = 0 if (lock_flush_tlb) flush_tlbs() mmu_unlock() // In invalidate range // MMU notifier mmu_lock() if (pte != 0) *ptep = 0 flush = true if (flush) flush_remote_tlbs() mmu_unlock() return // Host MM reallocates // page previously // backing guest memory. // Guest accesses // invalid page // through pte_1 // in its TLB!! Tested: Ran all kvm-unit-tests on a Intel Haswell machine with and without this patch. The patch introduced no new failures. Signed-off-by: Ben Gardon <bgardon@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* KVM: MMU: record maximum physical address width in kvm_mmu_extended_roleYu Zhang2019-02-221-0/+1
| | | | | | | | | | | | | | | | | Previously, commit 7dcd57552008 ("x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed") offered some optimization to avoid the unnecessary reconfiguration. Yet one scenario is broken - when cpuid changes VM's maximum physical address width, reconfiguration is needed to reset the reserved bits. Also, the TDP may need to reset its shadow_root_level when this value is changed. To fix this, a new field, maxphyaddr, is introduced in the extended role structure to keep track of the configured guest physical address width. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm: x86: Return LA57 feature based on hardware capabilityYu Zhang2019-02-221-0/+4
| | | | | | | | | | | | | | | | Previously, 'commit 372fddf70904 ("x86/mm: Introduce the 'no5lvl' kernel parameter")' cleared X86_FEATURE_LA57 in boot_cpu_data, if Linux chooses to not run in 5-level paging mode. Yet boot_cpu_data is queried by do_cpuid_ent() as the host capability later when creating vcpus, and Qemu will not be able to detect this feature and create VMs with LA57 feature. As discussed earlier, VMs can still benefit from extended linear address width, e.g. to enhance features like ASLR. So we would like to fix this, by return the true hardware capability when Qemu queries. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* x86/kvm/mmu: fix switch between root and guest MMUsVitaly Kuznetsov2019-02-221-4/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu") brought one subtle change: previously, when switching back from L2 to L1, we were resetting MMU hooks (like mmu->get_cr3()) in kvm_init_mmu() called from nested_vmx_load_cr3() and now we do that in nested_ept_uninit_mmu_context() when we re-target vcpu->arch.mmu pointer. The change itself looks logical: if nested_ept_init_mmu_context() changes something than nested_ept_uninit_mmu_context() restores it back. There is, however, one thing: the following call chain: nested_vmx_load_cr3() kvm_mmu_new_cr3() __kvm_mmu_new_cr3() fast_cr3_switch() cached_root_available() now happens with MMU hooks pointing to the new MMU (root MMU in our case) while previously it was happening with the old one. cached_root_available() tries to stash current root but it is incorrect to read current CR3 with mmu->get_cr3(), we need to use old_mmu->get_cr3() which in case we're switching from L2 to L1 is guest_mmu. (BTW, in shadow page tables case this is a non-issue because we don't switch MMU). While we could've tried to guess that we're switching between MMUs and call the right ->get_cr3() from cached_root_available() this seems to be overly complicated. Instead, just stash the corresponding CR3 when setting root_hpa and make cached_root_available() use the stashed value. Fixes: 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm: vmx: Fix entry number check for add_atomic_switch_msr()Xiaoyao Li2019-02-141-1/+2
| | | | | | | | | | | | Commit ca83b4a7f2d068da79a0 ("x86/KVM/VMX: Add find_msr() helper function") introduces the helper function find_msr(), which returns -ENOENT when not find the msr in vmx->msr_autoload.guest/host. Correct checking contion of no more available entry in vmx->msr_autoload. Fixes: ca83b4a7f2d0 ("x86/KVM/VMX: Add find_msr() helper function") Cc: stable@vger.kernel.org Signed-off-by: Xiaoyao Li <xiaoyao.li@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Recompute PID.ON when clearing PID.SNLuwei Kang2019-02-143-21/+17
| | | | | | | | | | | | | | | | | Some Posted-Interrupts from passthrough devices may be lost or overwritten when the vCPU is in runnable state. The SN (Suppress Notification) of PID (Posted Interrupt Descriptor) will be set when the vCPU is preempted (vCPU in KVM_MP_STATE_RUNNABLE state but not running on physical CPU). If a posted interrupt comes at this time, the irq remapping facility will set the bit of PIR (Posted Interrupt Requests) but not ON (Outstanding Notification). Then, the interrupt will not be seen by KVM, which always expects PID.ON=1 if PID.PIR=1 as documented in the Intel processor SDM but not in the VT-d specification. To fix this, restore the invariant after PID.SN is cleared. Signed-off-by: Luwei Kang <luwei.kang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: nVMX: Restore a preemption timer consistency checkSean Christopherson2019-02-131-0/+4
| | | | | | | | | | | A recently added preemption timer consistency check was unintentionally dropped when the consistency checks were being reorganized to match the SDM's ordering. Fixes: 461b4ba4c7ad ("KVM: nVMX: Move the checks for VM-Execution Control Fields to a separate helper function") Cc: Krish Sadhukhan <krish.sadhukhan@oracle.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* x86/kvm/nVMX: read from MSR_IA32_VMX_PROCBASED_CTLS2 only when it is availableVitaly Kuznetsov2019-02-121-3/+5
| | | | | | | | | | | | | | SDM says MSR_IA32_VMX_PROCBASED_CTLS2 is only available "If (CPUID.01H:ECX.[5] && IA32_VMX_PROCBASED_CTLS[63])". It was found that some old cpus (namely "Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz (family: 0x6, model: 0xf, stepping: 0x6") don't have it. Add the missing check. Reported-by: Zdenek Kaspar <zkaspar82@gmail.com> Tested-by: Zdenek Kaspar <zkaspar82@gmail.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: nVMX: unconditionally cancel preemption timer in free_nested ↵Peter Shier2019-02-071-0/+1
| | | | | | | | | | | | | | | | | | | | | (CVE-2019-7221) Bugzilla: 1671904 There are multiple code paths where an hrtimer may have been started to emulate an L1 VMX preemption timer that can result in a call to free_nested without an intervening L2 exit where the hrtimer is normally cancelled. Unconditionally cancel in free_nested to cover all cases. Embargoed until Feb 7th 2019. Signed-off-by: Peter Shier <pshier@google.com> Reported-by: Jim Mattson <jmattson@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Reported-by: Felix Wilhelm <fwilhelm@google.com> Cc: stable@kernel.org Message-Id: <20181011184646.154065-1-pshier@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: work around leak of uninitialized stack contents (CVE-2019-7222)Paolo Bonzini2019-02-071-0/+7
| | | | | | | | | | | | | | | | | | | Bugzilla: 1671930 Emulation of certain instructions (VMXON, VMCLEAR, VMPTRLD, VMWRITE with memory operand, INVEPT, INVVPID) can incorrectly inject a page fault when passed an operand that points to an MMIO address. The page fault will use uninitialized kernel stack memory as the CR2 and error code. The right behavior would be to abort the VM with a KVM_EXIT_INTERNAL_ERROR exit to userspace; however, it is not an easy fix, so for now just ensure that the error code and CR2 are zero. Embargoed until Feb 7th 2019. Reported-by: Felix Wilhelm <fwilhelm@google.com> Cc: stable@kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVMJosh Poimboeuf2019-01-301-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the following commit: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS") ... the hotplug code attempted to detect when SMT was disabled by BIOS, in which case it reported SMT as permanently disabled. However, that code broke a virt hotplug scenario, where the guest is booted with only primary CPU threads, and a sibling is brought online later. The problem is that there doesn't seem to be a way to reliably distinguish between the HW "SMT disabled by BIOS" case and the virt "sibling not yet brought online" case. So the above-mentioned commit was a bit misguided, as it permanently disabled SMT for both cases, preventing future virt sibling hotplugs. Going back and reviewing the original problems which were attempted to be solved by that commit, when SMT was disabled in BIOS: 1) /sys/devices/system/cpu/smt/control showed "on" instead of "notsupported"; and 2) vmx_vm_init() was incorrectly showing the L1TF_MSG_SMT warning. I'd propose that we instead consider #1 above to not actually be a problem. Because, at least in the virt case, it's possible that SMT wasn't disabled by BIOS and a sibling thread could be brought online later. So it makes sense to just always default the smt control to "on" to allow for that possibility (assuming cpuid indicates that the CPU supports SMT). The real problem is #2, which has a simple fix: change vmx_vm_init() to query the actual current SMT state -- i.e., whether any siblings are currently online -- instead of looking at the SMT "control" sysfs value. So fix it by: a) reverting the original "fix" and its followup fix: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS") bc2d8d262cba ("cpu/hotplug: Fix SMT supported evaluation") and b) changing vmx_vm_init() to query the actual current SMT state -- instead of the sysfs control value -- to determine whether the L1TF warning is needed. This also requires the 'sched_smt_present' variable to exported, instead of 'cpu_smt_control'. Fixes: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS") Reported-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Joe Mario <jmario@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/e3a85d585da28cc333ecbc1e78ee9216e6da9396.1548794349.git.jpoimboe@redhat.com
* KVM: x86: Mark expected switch fall-throughsGustavo A. R. Silva2019-01-256-4/+10
| | | | | | | | | | | | | | | | | | | | | | | | In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. This patch fixes the following warnings: arch/x86/kvm/lapic.c:1037:27: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/lapic.c:1876:3: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/hyperv.c:1637:6: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/svm.c:4396:6: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/mmu.c:4372:36: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/x86.c:3835:6: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/x86.c:7938:23: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/vmx/vmx.c:2015:6: warning: this statement may fall through [-Wimplicit-fallthrough=] arch/x86/kvm/vmx/vmx.c:1773:6: warning: this statement may fall through [-Wimplicit-fallthrough=] Warning level 3 was used: -Wimplicit-fallthrough=3 This patch is part of the ongoing efforts to enabling -Wimplicit-fallthrough. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: fix TRACE_INCLUDE_PATH and remove -I. header search pathsMasahiro Yamada2019-01-252-5/+1
| | | | | | | | | | | | | | | | | The header search path -I. in kernel Makefiles is very suspicious; it allows the compiler to search for headers in the top of $(srctree), where obviously no header file exists. The reason of having -I. here is to make the incorrectly set TRACE_INCLUDE_PATH working. As the comment block in include/trace/define_trace.h says, TRACE_INCLUDE_PATH should be a relative path to the define_trace.h Fix the TRACE_INCLUDE_PATH, and remove the iffy include paths. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* x86/kvm/hyper-v: nested_enable_evmcs() sets vmcs_version incorrectlyVitaly Kuznetsov2019-01-251-3/+4
| | | | | | | | | | | | | | Commit e2e871ab2f02 ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper") broke EVMCS enablement: to set vmcs_version we now call nested_get_evmcs_version() but this function checks enlightened_vmcs_enabled flag which is not yet set so we end up returning zero. Fix the issue by re-arranging things in nested_enable_evmcs(). Fixes: e2e871ab2f02 ("x86/kvm/hyper-v: Introduce nested_get_evmcs_version() helper") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: VMX: Move vmx_vcpu_run()'s VM-Enter asm blob to a helper functionSean Christopherson2019-01-251-66/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ...along with the function's STACK_FRAME_NON_STANDARD tag. Moving the asm blob results in a significantly smaller amount of code that is marked with STACK_FRAME_NON_STANDARD, which makes it far less likely that gcc will split the function and trigger a spurious objtool warning. As a bonus, removing STACK_FRAME_NON_STANDARD from vmx_vcpu_run() allows the bulk of code to be properly checked by objtool. Because %rbp is not loaded via VMCS fields, vmx_vcpu_run() must manually save/restore the host's RBP and load the guest's RBP prior to calling vmx_vmenter(). Modifying %rbp triggers objtool's stack validation code, and so vmx_vcpu_run() is tagged with STACK_FRAME_NON_STANDARD since it's impossible to avoid modifying %rbp. Unfortunately, vmx_vcpu_run() is also a gigantic function that gcc will split into separate functions, e.g. so that pieces of the function can be inlined. Splitting the function means that the compiled Elf file will contain one or more vmx_vcpu_run.part.* functions in addition to a vmx_vcpu_run function. Depending on where the function is split, objtool may warn about a "call without frame pointer save/setup" in vmx_vcpu_run.part.* since objtool's stack validation looks for exact names when whitelisting functions tagged with STACK_FRAME_NON_STANDARD. Up until recently, the undesirable function splitting was effectively blocked because vmx_vcpu_run() was tagged with __noclone. At the time, __noclone had an unintended side effect that put vmx_vcpu_run() into a separate optimization unit, which in turn prevented gcc from inlining the function (or any of its own function calls) and thus eliminated gcc's motivation to split the function. Removing the __noclone attribute allowed gcc to optimize vmx_vcpu_run(), exposing the objtool warning. Kudos to Qian Cai for root causing that the fnsplit optimization is what caused objtool to complain. Fixes: 453eafbe65f7 ("KVM: VMX: Move VM-Enter + VM-Exit handling to non-inline sub-routines") Tested-by: Qian Cai <cai@lca.pw> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm: vmx: fix some -Wmissing-prototypes warningsYi Wang2019-01-252-2/+2
| | | | | | | | | | | We get some warnings when building kernel with W=1: arch/x86/kvm/vmx/vmx.c:426:5: warning: no previous prototype for ‘kvm_fill_hv_flush_list_func’ [-Wmissing-prototypes] arch/x86/kvm/vmx/nested.c:58:6: warning: no previous prototype for ‘init_vmcs_shadow_fields’ [-Wmissing-prototypes] Make them static to fix this. Signed-off-by: Yi Wang <wang.yi59@zte.com.cn> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: nSVM: clear events pending from svm_complete_interrupts() when exiting ↵Vitaly Kuznetsov2019-01-251-0/+8
| | | | | | | | | | | | | | | | | to L1 kvm-unit-tests' eventinj "NMI failing on IDT" test results in NMI being delivered to the host (L1) when it's running nested. The problem seems to be: svm_complete_interrupts() raises 'nmi_injected' flag but later we decide to reflect EXIT_NPF to L1. The flag remains pending and we do NMI injection upon entry so it got delivered to L1 instead of L2. It seems that VMX code solves the same issue in prepare_vmcs12(), this was introduced with code refactoring in commit 5f3d5799974b ("KVM: nVMX: Rework event injection and recovery"). Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* svm: Fix AVIC incomplete IPI emulationSuravee Suthikulpanit2019-01-251-15/+4
| | | | | | | | | | | | In case of incomplete IPI with invalid interrupt type, the current SVM driver does not properly emulate the IPI, and fails to boot FreeBSD guests with multiple vcpus when enabling AVIC. Fix this by update APIC ICR high/low registers, which also emulate sending the IPI. Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* svm: Add warning message for AVIC IPI invalid targetSuravee Suthikulpanit2019-01-251-0/+2
| | | | | | | | | | | Print warning message when IPI target ID is invalid due to one of the following reasons: * In logical mode: cluster > max_cluster (64) * In physical mode: target > max_physical (512) * Address is not present in the physical or logical ID tables Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Fix PV IPIs for 32-bit KVM hostSean Christopherson2019-01-251-1/+1
| | | | | | | | | | | | | | The recognition of the KVM_HC_SEND_IPI hypercall was unintentionally wrapped in "#ifdef CONFIG_X86_64", causing 32-bit KVM hosts to reject any and all PV IPI requests despite advertising the feature. This results in all KVM paravirtualized guests hanging during SMP boot due to IPIs never being delivered. Fixes: 4180bf1b655a ("KVM: X86: Implement "send IPI" hypercall") Cc: stable@vger.kernel.org Cc: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* x86/kvm/hyper-v: recommend using eVMCS only when it is enabledVitaly Kuznetsov2019-01-251-1/+2
| | | | | | | | | | | We shouldn't probably be suggesting using Enlightened VMCS when it's not enabled (not supported from guest's point of view). Hyper-V on KVM seems to be fine either way but let's be consistent. Fixes: 2bc39970e932 ("x86/kvm/hyper-v: Introduce KVM_GET_SUPPORTED_HV_CPUID") Reviewed-by: Liran Alon <liran.alon@oracle.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* x86/kvm/hyper-v: don't recommend doing reset via synthetic MSRVitaly Kuznetsov2019-01-251-1/+0
| | | | | | | | | | System reset through synthetic MSR is not recommended neither by genuine Hyper-V nor my QEMU. Fixes: 2bc39970e932 ("x86/kvm/hyper-v: Introduce KVM_GET_SUPPORTED_HV_CPUID") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Liran Alon <liran.alon@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm: x86/vmx: Use kzalloc for cached_vmcs12Tom Roeder2019-01-251-4/+8
| | | | | | | | | | | | | | | | | | | | This changes the allocation of cached_vmcs12 to use kzalloc instead of kmalloc. This removes the information leak found by Syzkaller (see Reported-by) in this case and prevents similar leaks from happening based on cached_vmcs12. It also changes vmx_get_nested_state to copy out the full 4k VMCS12_SIZE in copy_to_user rather than only the size of the struct. Tested: rebuilt against head, booted, and ran the syszkaller repro https://syzkaller.appspot.com/text?tag=ReproC&x=174efca3400000 without observing any problems. Reported-by: syzbot+ded1696f6b50b615b630@syzkaller.appspotmail.com Fixes: 8fcc4b5923af5de58b80b53a069453b135693304 Cc: stable@vger.kernel.org Signed-off-by: Tom Roeder <tmroeder@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: VMX: Use the correct field var when clearing ↵Sean Christopherson2019-01-251-1/+1
| | | | | | | | | | | | | VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL Fix a recently introduced bug that results in the wrong VMCS control field being updated when applying a IA32_PERF_GLOBAL_CTRL errata. Fixes: c73da3fcab43 ("KVM: VMX: Properly handle dynamic VM Entry/Exit controls") Reported-by: Harald Arnesen <harald@skogtun.org> Tested-by: Harald Arnesen <harald@skogtun.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Fix single-step debuggingAlexander Popov2019-01-251-2/+1
| | | | | | | | | | | | | | | | | | | The single-step debugging of KVM guests on x86 is broken: if we run gdb 'stepi' command at the breakpoint when the guest interrupts are enabled, RIP always jumps to native_apic_mem_write(). Then other nasty effects follow. Long investigation showed that on Jun 7, 2017 the commit c8401dda2f0a00cd25c0 ("KVM: x86: fix singlestepping over syscall") introduced the kvm_run.debug corruption: kvm_vcpu_do_singlestep() can be called without X86_EFLAGS_TF set. Let's fix it. Please consider that for -stable. Signed-off-by: Alexander Popov <alex.popov@linux.com> Cc: stable@vger.kernel.org Fixes: c8401dda2f0a00cd25c0 ("KVM: x86: fix singlestepping over syscall") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* x86/kvm/hyper-v: don't announce GUEST IDLE MSR supportVitaly Kuznetsov2019-01-251-1/+0
| | | | | | | | | | HV_X64_MSR_GUEST_IDLE_AVAILABLE appeared in kvm_vcpu_ioctl_get_hv_cpuid() by mistake: it announces support for HV_X64_MSR_GUEST_IDLE (0x400000F0) which we don't support in KVM (yet). Fixes: 2bc39970e932 ("x86/kvm/hyper-v: Introduce KVM_GET_SUPPORTED_HV_CPUID") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* x86/kvm/nVMX: don't skip emulated instruction twice when vmptr address is ↵Vitaly Kuznetsov2019-01-111-2/+1
| | | | | | | | | | | | | | | | not backed Since commit 09abb5e3e5e50 ("KVM: nVMX: call kvm_skip_emulated_instruction in nested_vmx_{fail,succeed}") nested_vmx_failValid() results in kvm_skip_emulated_instruction() so doing it again in handle_vmptrld() when vmptr address is not backed is wrong, we end up advancing RIP twice. Fixes: fca91f6d60b6e ("kvm: nVMX: Set VM instruction error for VMPTRLD of unbacked page") Reported-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
* KVM/VMX: Avoid return error when flush tlb successfully in the ↵Lan Tianyu2019-01-111-1/+1
| | | | | | | | | | | | | | hv_remote_flush_tlb_with_range() The "ret" is initialized to be ENOTSUPP. The return value of __hv_remote_flush_tlb_with_range() will be Or with "ret" when ept table potiners are mismatched. This will cause return ENOTSUPP even if flush tlb successfully. This patch is to fix the issue and set "ret" to 0. Fixes: a5c214dad198 ("KVM/VMX: Change hv flush logic when ept tables are mismatched.") Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
* kvm: sev: Fail KVM_SEV_INIT if already initializedDavid Rientjes2019-01-111-0/+3
| | | | | | | | | | | | | | | By code inspection, it was found that multiple calls to KVM_SEV_INIT could deplete asid bits and overwrite kvm_sev_info's regions_list. Multiple calls to KVM_SVM_INIT is not likely to occur with QEMU, but this should likely be fixed anyway. This code is serialized by kvm->lock. Fixes: 1654efcbc431 ("KVM: SVM: Add KVM_SEV_INIT command") Reported-by: Cfir Cohen <cfir@google.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
* KVM: x86: Fix bit shifting in update_intel_pt_cfgGustavo A. R. Silva2019-01-111-1/+1
| | | | | | | | | | | | | | ctl_bitmask in pt_desc is of type u64. When an integer like 0xf is being left shifted more than 32 bits, the behavior is undefined. Fix this by adding suffix ULL to integer 0xf. Addresses-Coverity-ID: 1476095 ("Bad bit shift operation") Fixes: 6c0f0bba85a0 ("KVM: x86: Introduce a function to initialize the PT configuration") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Luwei Kang <luwei.kang@intel.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
* jump_label: move 'asm goto' support test to KconfigMasahiro Yamada2019-01-061-1/+1
| | | | | | | | | | | | | | | | | | | | | Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label". The jump label is controlled by HAVE_JUMP_LABEL, which is defined like this: #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) # define HAVE_JUMP_LABEL #endif We can improve this by testing 'asm goto' support in Kconfig, then make JUMP_LABEL depend on CC_HAS_ASM_GOTO. Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will match to the real kernel capability. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
* Merge tag 'kconfig-v4.21' of ↵Linus Torvalds2018-12-291-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kconfig updates from Masahiro Yamada: - support -y option for merge_config.sh to avoid downgrading =y to =m - remove S_OTHER symbol type, and touch include/config/*.h files correctly - fix file name and line number in lexer warnings - fix memory leak when EOF is encountered in quotation - resolve all shift/reduce conflicts of the parser - warn no new line at end of file - make 'source' statement more strict to take only string literal - rewrite the lexer and remove the keyword lookup table - convert to SPDX License Identifier - compile C files independently instead of including them from zconf.y - fix various warnings of gconfig - misc cleanups * tag 'kconfig-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits) kconfig: surround dbg_sym_flags with #ifdef DEBUG to fix gconf warning kconfig: split images.c out of qconf.cc/gconf.c to fix gconf warnings kconfig: add static qualifiers to fix gconf warnings kconfig: split the lexer out of zconf.y kconfig: split some C files out of zconf.y kconfig: convert to SPDX License Identifier kconfig: remove keyword lookup table entirely kconfig: update current_pos in the second lexer kconfig: switch to ASSIGN_VAL state in the second lexer kconfig: stop associating kconf_id with yylval kconfig: refactor end token rules kconfig: stop supporting '.' and '/' in unquoted words treewide: surround Kconfig file paths with double quotes microblaze: surround string default in Kconfig with double quotes kconfig: use T_WORD instead of T_VARIABLE for variables kconfig: use specific tokens instead of T_ASSIGN for assignments kconfig: refactor scanning and parsing "option" properties kconfig: use distinct tokens for type and default properties kconfig: remove redundant token defines kconfig: rename depends_list to comment_option_list ...
| * treewide: surround Kconfig file paths with double quotesMasahiro Yamada2018-12-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Kconfig lexer supports special characters such as '.' and '/' in the parameter context. In my understanding, the reason is just to support bare file paths in the source statement. I do not see a good reason to complicate Kconfig for the room of ambiguity. The majority of code already surrounds file paths with double quotes, and it makes sense since file paths are constant string literals. Make it treewide consistent now. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Wolfram Sang <wsa@the-dreams.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Ingo Molnar <mingo@kernel.org>
* | Merge branch 'x86-cleanups-for-linus' of ↵Linus Torvalds2018-12-261-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Misc cleanups" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kprobes: Remove trampoline_handler() prototype x86/kernel: Fix more -Wmissing-prototypes warnings x86: Fix various typos in comments x86/headers: Fix -Wmissing-prototypes warning x86/process: Avoid unnecessary NULL check in get_wchan() x86/traps: Complete prototype declarations x86/mce: Fix -Wmissing-prototypes warnings x86/gart: Rewrite early_gart_iommu_check() comment
| * | x86: Fix various typos in commentsIngo Molnar2018-12-032-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Go over arch/x86/ and fix common typos in comments, and a typo in an actual function argument name. No change in functionality intended. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2018-12-2626-15449/+16669
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull KVM updates from Paolo Bonzini: "ARM: - selftests improvements - large PUD support for HugeTLB - single-stepping fixes - improved tracing - various timer and vGIC fixes x86: - Processor Tracing virtualization - STIBP support - some correctness fixes - refactorings and splitting of vmx.c - use the Hyper-V range TLB flush hypercall - reduce order of vcpu struct - WBNOINVD support - do not use -ftrace for __noclone functions - nested guest support for PAUSE filtering on AMD - more Hyper-V enlightenments (direct mode for synthetic timers) PPC: - nested VFIO s390: - bugfixes only this time" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (171 commits) KVM: x86: Add CPUID support for new instruction WBNOINVD kvm: selftests: ucall: fix exit mmio address guessing Revert "compiler-gcc: disable -ftracer for __noclone functions" KVM: VMX: Move VM-Enter + VM-Exit handling to non-inline sub-routines KVM: VMX: Explicitly reference RCX as the vmx_vcpu pointer in asm blobs KVM: x86: Use jmp to invoke kvm_spurious_fault() from .fixup MAINTAINERS: Add arch/x86/kvm sub-directories to existing KVM/x86 entry KVM/x86: Use SVM assembly instruction mnemonics instead of .byte streams KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range() KVM/MMU: Flush tlb directly in kvm_set_pte_rmapp() KVM/MMU: Move tlb flush in kvm_set_pte_rmapp() to kvm_mmu_notifier_change_pte() KVM: Make kvm_set_spte_hva() return int KVM: Replace old tlb flush function with new one to flush a specified range. KVM/MMU: Add tlb flush with range helper function KVM/VMX: Add hv tlb range flush support x86/hyper-v: Add HvFlushGuestAddressList hypercall support KVM: Add tlb_remote_flush_with_range callback in kvm_x86_ops KVM: x86: Disable Intel PT when VMXON in L1 guest KVM: x86: Set intercept for Intel PT MSRs read/write KVM: x86: Implement Intel PT MSRs read/write emulation ...
| * | | KVM: x86: Add CPUID support for new instruction WBNOINVDRobert Hoo2018-12-211-1/+1
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Robert Hoo <robert.hu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | KVM: VMX: Move VM-Enter + VM-Exit handling to non-inline sub-routinesSean Christopherson2018-12-215-34/+78
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Transitioning to/from a VMX guest requires KVM to manually save/load the bulk of CPU state that the guest is allowed to direclty access, e.g. XSAVE state, CR2, GPRs, etc... For obvious reasons, loading the guest's GPR snapshot prior to VM-Enter and saving the snapshot after VM-Exit is done via handcoded assembly. The assembly blob is written as inline asm so that it can easily access KVM-defined structs that are used to hold guest state, e.g. moving the blob to a standalone assembly file would require generating defines for struct offsets. The other relevant aspect of VMX transitions in KVM is the handling of VM-Exits. KVM doesn't employ a separate VM-Exit handler per se, but rather treats the VMX transition as a mega instruction (with many side effects), i.e. sets the VMCS.HOST_RIP to a label immediately following VMLAUNCH/VMRESUME. The label is then exposed to C code via a global variable definition in the inline assembly. Because of the global variable, KVM takes steps to (attempt to) ensure only a single instance of the owning C function, e.g. vmx_vcpu_run, is generated by the compiler. The earliest approach placed the inline assembly in a separate noinline function[1]. Later, the assembly was folded back into vmx_vcpu_run() and tagged with __noclone[2][3], which is still used today. After moving to __noclone, an edge case was encountered where GCC's -ftracer optimization resulted in the inline assembly blob being duplicated. This was "fixed" by explicitly disabling -ftracer in the __noclone definition[4]. Recently, it was found that disabling -ftracer causes build warnings for unsuspecting users of __noclone[5], and more importantly for KVM, prevents the compiler for properly optimizing vmx_vcpu_run()[6]. And perhaps most importantly of all, it was pointed out that there is no way to prevent duplication of a function with 100% reliability[7], i.e. more edge cases may be encountered in the future. So to summarize, the only way to prevent the compiler from duplicating the global variable definition is to move the variable out of inline assembly, which has been suggested several times over[1][7][8]. Resolve the aforementioned issues by moving the VMLAUNCH+VRESUME and VM-Exit "handler" to standalone assembly sub-routines. Moving only the core VMX transition codes allows the struct indexing to remain as inline assembly and also allows the sub-routines to be used by nested_vmx_check_vmentry_hw(). Reusing the sub-routines has a happy side-effect of eliminating two VMWRITEs in the nested_early_check path as there is no longer a need to dynamically change VMCS.HOST_RIP. Note that callers to vmx_vmenter() must account for the CALL modifying RSP, e.g. must subtract op-size from RSP when synchronizing RSP with VMCS.HOST_RSP and "restore" RSP prior to the CALL. There are no great alternatives to fudging RSP. Saving RSP in vmx_enter() is difficult because doing so requires a second register (VMWRITE does not provide an immediate encoding for the VMCS field and KVM supports Hyper-V's memory-based eVMCS ABI). The other more drastic alternative would be to use eschew VMCS.HOST_RSP and manually save/load RSP using a per-cpu variable (which can be encoded as e.g. gs:[imm]). But because a valid stack is needed at the time of VM-Exit (NMIs aren't blocked and a user could theoretically insert INT3/INT1ICEBRK at the VM-Exit handler), a dedicated per-cpu VM-Exit stack would be required. A dedicated stack isn't difficult to implement, but it would require at least one page per CPU and knowledge of the stack in the dumpstack routines. And in most cases there is essentially zero overhead in dynamically updating VMCS.HOST_RSP, e.g. the VMWRITE can be avoided for all but the first VMLAUNCH unless nested_early_check=1, which is not a fast path. In other words, avoiding the VMCS.HOST_RSP by using a dedicated stack would only make the code marginally less ugly while requiring at least one page per CPU and forcing the kernel to be aware (and approve) of the VM-Exit stack shenanigans. [1] cea15c24ca39 ("KVM: Move KVM context switch into own function") [2] a3b5ba49a8c5 ("KVM: VMX: add the __noclone attribute to vmx_vcpu_run") [3] 104f226bfd0a ("KVM: VMX: Fold __vmx_vcpu_run() into vmx_vcpu_run()") [4] 95272c29378e ("compiler-gcc: disable -ftracer for __noclone functions") [5] https://lkml.kernel.org/r/20181218140105.ajuiglkpvstt3qxs@treble [6] https://patchwork.kernel.org/patch/8707981/#21817015 [7] https://lkml.kernel.org/r/ri6y38lo23g.fsf@suse.cz [8] https://lkml.kernel.org/r/20181218212042.GE25620@tassilo.jf.intel.com Suggested-by: Andi Kleen <ak@linux.intel.com> Suggested-by: Martin Jambor <mjambor@suse.cz> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Nadav Amit <namit@vmware.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Martin Jambor <mjambor@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * | | KVM: VMX: Explicitly reference RCX as the vmx_vcpu pointer in asm blobsSean Christopherson2018-12-212-42/+50
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use '%% " _ASM_CX"' instead of '%0' to dereference RCX, i.e. the 'struct vcpu_vmx' pointer, in the VM-Enter asm blobs of vmx_vcpu_run() and nested_vmx_check_vmentry_hw(). Using the symbolic name means that adding/removing an output parameter(s) requires "rewriting" almost all of the asm blob, which makes it nearly impossible to understand what's being changed in even the most minor patches. Opportunistically improve the code comments. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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