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* [S390] move sie code to entry.SMartin Schwidefsky2011-07-241-98/+0
| | | | | | | | | | | | | | The entry to / exit from sie has subtle dependencies to the first level interrupt handler. Move the sie assembler code to entry64.S and replace the SIE_HOOK callback with a test and the new _TIF_SIE bit. In addition this patch fixes several problems in regard to the check for the_TIF_EXIT_SIE bits. The old code checked the TIF bits before executing the interrupt handler and it only modified the instruction address if it pointed directly to the sie instruction. In both cases it could miss a TIF bit that normally would cause an exit from the guest and would reenter the guest context. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] kvm-s390: Fix host crash on misbehaving guestsChristian Borntraeger2011-06-061-0/+2
| | | | | | | | | | | | | | | | | | | commit 9ff4cfb3fcfd48b49fdd9be7381b3be340853aa4 ([S390] kvm-390: Let kernel exit SIE instruction on work) fixed a problem of commit commit cd3b70f5d4d82f85d1e1d6e822f38ae098cf7c72 ([S390] virtualization aware cpu measurement) but uncovered another one. If a kvm guest accesses guest real memory that doesnt exist, the page fault handler calls the sie hook, which then rewrites the return psw from sie_inst to either sie_exit or sie_reenter. On return, the page fault handler will then detect the wrong access as a kernel fault causing a kernel oops in sie_reenter or sie_exit. We have to add these two addresses to the exception table to allow graceful exits. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] kvm-390: Let kernel exit SIE instruction on workCarsten Otte2011-04-201-2/+2
| | | | | | | | | | | | | | | | From: Christian Borntraeger <borntraeger@de.ibm.com> This patch fixes the sie exit on interrupts. The low level interrupt handler returns to the PSW address in pt_regs and not to the PSW address in the lowcore. Without this fix a cpu bound guest might never leave guest state since the host interrupt handler would blindly return to the SIE instruction, even on need_resched and friends. Cc: stable@kernel.org Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] spp: remove KVM_AWARE_CMF config optionHeiko Carstens2010-05-261-3/+1
| | | | | | | | | | | This config option enables or disables three single instructions which aren't expensive. This is too fine grained. Besided that everybody who uses kvm would enable it anyway in order to debug performance problems. Just remove it. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* [S390] virtualization aware cpu measurementCarsten Otte2010-05-171-13/+64
| | | | | | | | Use the SPP instruction to set a tag on entry to / exit of the virtual machine context. This allows the cpu measurement facility to distinguish the samples from the host and the different guests. Signed-off-by: Carsten Otte <cotte@de.ibm.com>
* KVM: s390: arch backend for the kvm kernel moduleHeiko Carstens2008-04-271-0/+47
This patch contains the port of Qumranet's kvm kernel module to IBM zSeries (aka s390x, mainframe) architecture. It uses the mainframe's virtualization instruction SIE to run virtual machines with up to 64 virtual CPUs each. This port is only usable on 64bit host kernels, and can only run 64bit guest kernels. However, running 31bit applications in guest userspace is possible. The following source files are introduced by this patch arch/s390/kvm/kvm-s390.c similar to arch/x86/kvm/x86.c, this implements all arch callbacks for kvm. __vcpu_run calls back into sie64a to enter the guest machine context arch/s390/kvm/sie64a.S assembler function sie64a, which enters guest context via SIE, and switches world before and after that include/asm-s390/kvm_host.h contains all vital data structures needed to run virtual machines on the mainframe include/asm-s390/kvm.h defines kvm_regs and friends for user access to guest register content arch/s390/kvm/gaccess.h functions similar to uaccess to access guest memory arch/s390/kvm/kvm-s390.h header file for kvm-s390 internals, extended by later patches Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
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