[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen stable-4.8] x86: ignore guest microcode loading attempts
commit ce185fbce2912702eef295afb31dc4ba163c06b6 Author: Jan Beulich <jbeulich@xxxxxxxx> AuthorDate: Fri Mar 16 17:19:20 2018 +0100 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Fri Mar 16 17:19:20 2018 +0100 x86: ignore guest microcode loading attempts The respective MSRs are write-only, and hence attempts by guests to write to these are - as of 1f1d183d49 ("x86/HVM: don't give the wrong impression of WRMSR succeeding") no longer ignored. Restore original behavior for the two affected MSRs. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> master commit: 59c0983e10d70ea2368085271b75fb007811fe52 master date: 2018-03-15 12:44:24 +0100 --- xen/arch/x86/hvm/hvm.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 2e6775ba5d..96afb7b1c2 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -3927,6 +3927,8 @@ int hvm_msr_read_intercept(unsigned int msr, uint64_t *msr_content) goto gp_fault; break; + case MSR_AMD_PATCHLOADER: + case MSR_IA32_UCODE_WRITE: case MSR_PRED_CMD: /* Write-only */ goto gp_fault; @@ -4092,6 +4094,26 @@ int hvm_msr_write_intercept(unsigned int msr, uint64_t msr_content, goto gp_fault; break; + case MSR_AMD_PATCHLOADER: + /* + * See note on MSR_IA32_UCODE_WRITE below, which may or may not apply + * to AMD CPUs as well (at least the architectural/CPUID part does). + */ + if ( v->domain->arch.x86_vendor != X86_VENDOR_AMD ) + goto gp_fault; + break; + + case MSR_IA32_UCODE_WRITE: + /* + * Some versions of Windows at least on certain hardware try to load + * microcode before setting up an IDT. Therefore we must not inject #GP + * for such attempts. Also the MSR is architectural and not qualified + * by any CPUID bit. + */ + if ( v->domain->arch.x86_vendor != X86_VENDOR_INTEL ) + goto gp_fault; + break; + case MSR_IA32_XSS: ecx = 1; hvm_cpuid(XSTATE_CPUID, &eax, NULL, &ecx, NULL); -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.8 _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/xen-changelog
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