On 2018-01-03 23:31, Jim Mattson wrote: > Guest GPR values are live in the hardware GPRs at VM-exit. Do not > leave any guest values in hardware GPRs after the guest GPR values are > saved to the vcpu_vmx structure. > > This is a partial mitigation for CVE 2017-5715 and CVE 2017-5753. > Specifically, it defeats the Project Zero PoC for CVE 2017-5715. > > Suggested-by: Eric Northup <digitaleric@xxxxxxxxxx> > Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx> > Reviewed-by: Eric Northup <digitaleric@xxxxxxxxxx> > Reviewed-by: Benjamin Serebrin <serebrin@xxxxxxxxxx> > Reviewed-by: Andrew Honig <ahonig@xxxxxxxxxx> > --- > arch/x86/kvm/vmx.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 669f5f74857d..850baff9d107 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -9649,6 +9649,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) > /* Save guest registers, load host registers, keep flags */ > "mov %0, %c[wordsize](%%" _ASM_SP ") \n\t" > "pop %0 \n\t" > + "setbe %c[fail](%0)\n\t" > "mov %%" _ASM_AX ", %c[rax](%0) \n\t" > "mov %%" _ASM_BX ", %c[rbx](%0) \n\t" > __ASM_SIZE(pop) " %c[rcx](%0) \n\t" > @@ -9665,12 +9666,23 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) > "mov %%r13, %c[r13](%0) \n\t" > "mov %%r14, %c[r14](%0) \n\t" > "mov %%r15, %c[r15](%0) \n\t" > + "xor %%r8d, %%r8d \n\t" > + "xor %%r9d, %%r9d \n\t" > + "xor %%r10d, %%r10d \n\t" > + "xor %%r11d, %%r11d \n\t" > + "xor %%r12d, %%r12d \n\t" > + "xor %%r13d, %%r13d \n\t" > + "xor %%r14d, %%r14d \n\t" > + "xor %%r15d, %%r15d \n\t" > #endif > "mov %%cr2, %%" _ASM_AX " \n\t" > "mov %%" _ASM_AX ", %c[cr2](%0) \n\t" > > + "xor %%eax, %%eax \n\t" > + "xor %%ebx, %%ebx \n\t" > + "xor %%esi, %%esi \n\t" > + "xor %%edi, %%edi \n\t" > "pop %%" _ASM_BP "; pop %%" _ASM_DX " \n\t" > - "setbe %c[fail](%0) \n\t" > ".pushsection .rodata \n\t" > ".global vmx_return \n\t" > "vmx_return: " _ASM_PTR " 2b \n\t" > Shouldn't this be done on AMD as well, or is the answer "microcode update" there? Jan
