target/i386: Allow MCDT_NO if host supports
MCDT_NO bit indicates HW contains the security fix and doesn't need to
be mitigated to avoid data-dependent behaviour for certain instructions.
It needs no hypervisor support. Treat it as supported regardless of what
KVM reports.
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20230706054949.66556-4-tao1.su@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index de53184..ebfaf3d 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -432,6 +432,10 @@
uint32_t eax;
host_cpuid(7, 1, &eax, &unused, &unused, &unused);
ret |= eax & (CPUID_7_1_EAX_FZRM | CPUID_7_1_EAX_FSRS | CPUID_7_1_EAX_FSRC);
+ } else if (function == 7 && index == 2 && reg == R_EDX) {
+ uint32_t edx;
+ host_cpuid(7, 2, &unused, &unused, &unused, &edx);
+ ret |= edx & CPUID_7_2_EDX_MCDT_NO;
} else if (function == 0xd && index == 0 &&
(reg == R_EAX || reg == R_EDX)) {
/*
