diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2018-02-22 16:43:17 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-08 22:41:24 -0800 |
| commit | 0d62a56dc454699790a43a57ffa4258ff909b3f5 (patch) | |
| tree | 4df91fb125e09fec189c93848d435ea97fe08ccd /arch/x86/kvm/svm.c | |
| parent | 7135aaf3ed637b298e7df848095ea53f24c1a8f8 (diff) | |
KVM/x86: Remove indirect MSR op calls from SPEC_CTRL
commit ecb586bd29c99fb4de599dec388658e74388daad upstream.
Having a paravirt indirect call in the IBRS restore path is not a
good idea, since we are trying to protect from speculative execution
of bogus indirect branch targets. It is also slower, so use
native_wrmsrl() on the vmentry path too.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: KarimAllah Ahmed <karahmed@amazon.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: d28b387fb74da95d69d2615732f50cceb38e9a4d
Link: http://lkml.kernel.org/r/20180222154318.20361-2-pbonzini@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index e0bc3ad0f6cd..88348ec8cc34 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -45,6 +45,7 @@ #include <asm/debugreg.h> #include <asm/kvm_para.h> #include <asm/irq_remapping.h> +#include <asm/microcode.h> #include <asm/nospec-branch.h> #include <asm/virtext.h> @@ -5015,7 +5016,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) * being speculatively taken. */ if (svm->spec_ctrl) - wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl); + native_wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl); asm volatile ( "push %%" _ASM_BP "; \n\t" @@ -5125,10 +5126,10 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) * save it. */ if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL)) - rdmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl); + svm->spec_ctrl = native_read_msr(MSR_IA32_SPEC_CTRL); if (svm->spec_ctrl) - wrmsrl(MSR_IA32_SPEC_CTRL, 0); + native_wrmsrl(MSR_IA32_SPEC_CTRL, 0); /* Eliminate branch target predictions from guest mode */ vmexit_fill_RSB(); |