2018-01-07 11:40 GMT+01:00 Jan Kiszka <jan.kiszka@xxxxxx>: > 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 Paolo added it, already in linus tree Linux 4.15-rc7 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0cb5b30698fdc8f6b4646012e3acb4ddce430788 Jack
