On 2018-01-08 09:58, Jack Wang wrote: > 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 Thanks, I didn't noticed this. Jan
