diff options
Diffstat (limited to 'freed-ora/current/f20/x86-kvm-Clear-paravirt_enabled-on-KVM-guests-for-esp.patch')
| -rw-r--r-- | freed-ora/current/f20/x86-kvm-Clear-paravirt_enabled-on-KVM-guests-for-esp.patch | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/freed-ora/current/f20/x86-kvm-Clear-paravirt_enabled-on-KVM-guests-for-esp.patch b/freed-ora/current/f20/x86-kvm-Clear-paravirt_enabled-on-KVM-guests-for-esp.patch new file mode 100644 index 000000000..ba6928d89 --- /dev/null +++ b/freed-ora/current/f20/x86-kvm-Clear-paravirt_enabled-on-KVM-guests-for-esp.patch @@ -0,0 +1,73 @@ +From 0fdb006a5af7f391a6de4ce810aba4af46c427e4 Mon Sep 17 00:00:00 2001 +From: Andy Lutomirski <luto@amacapital.net> +Date: Fri, 5 Dec 2014 19:03:28 -0800 +Subject: [PATCH] x86, kvm: Clear paravirt_enabled on KVM guests for espfix32's + benefit + +paravirt_enabled has the following effects: + + - Disables the F00F bug workaround warning. There is no F00F bug + workaround any more because Linux's standard IDT handling already + works around the F00F bug, but the warning still exists. This + is only cosmetic, and, in any event, there is no such thing as + KVM on a CPU with the F00F bug. + + - Disables 32-bit APM BIOS detection. On a KVM paravirt system, + there should be no APM BIOS anyway. + + - Disables tboot. I think that the tboot code should check the + CPUID hypervisor bit directly if it matters. + + - paravirt_enabled disables espfix32. espfix32 should *not* be + disabled under KVM paravirt. + +The last point is the purpose of this patch. It fixes a leak of the +high 16 bits of the kernel stack address on 32-bit KVM paravirt +guests. + +While I'm at it, this removes pv_info setup from kvmclock. That +code seems to serve no purpose. + +Cc: stable@vger.kernel.org +Signed-off-by: Andy Lutomirski <luto@amacapital.net> +--- + arch/x86/kernel/kvm.c | 9 ++++++++- + arch/x86/kernel/kvmclock.c | 2 -- + 2 files changed, 8 insertions(+), 3 deletions(-) + +diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c +index 3dd8e2c4d74a..07de51f66deb 100644 +--- a/arch/x86/kernel/kvm.c ++++ b/arch/x86/kernel/kvm.c +@@ -282,7 +282,14 @@ NOKPROBE_SYMBOL(do_async_page_fault); + static void __init paravirt_ops_setup(void) + { + pv_info.name = "KVM"; +- pv_info.paravirt_enabled = 1; ++ ++ /* ++ * KVM isn't paravirt in the sense of paravirt_enabled. A KVM ++ * guest kernel works like a bare metal kernel with additional ++ * features, and paravirt_enabled is about features that are ++ * missing. ++ */ ++ pv_info.paravirt_enabled = 0; + + if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY)) + pv_cpu_ops.io_delay = kvm_io_delay; +diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c +index d9156ceecdff..d4d9a8ad7893 100644 +--- a/arch/x86/kernel/kvmclock.c ++++ b/arch/x86/kernel/kvmclock.c +@@ -263,8 +263,6 @@ void __init kvmclock_init(void) + #endif + kvm_get_preset_lpj(); + clocksource_register_hz(&kvm_clock, NSEC_PER_SEC); +- pv_info.paravirt_enabled = 1; +- pv_info.name = "KVM"; + + if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT)) + pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT); +-- +2.1.0 + |
