On Fri, Jun 01, 2018 at 11:38:08AM -0400, Konrad Rzeszutek Wilk wrote: > AMD future CPUs expose _two_ ways to utilize the Intel equivalant > of the Speculative Store Bypass Disable. The first is via > the virtualized VIRT_SPEC CTRL MSR (0xC001_011f) and the second > is via the SPEC_CTRL MSR (0x48). The document titled: > 124441_AMD64_SpeculativeStoreBypassDisable_Whitepaper_final.pdf > > gives priority of SPEC CTRL MSR over the VIRT SPEC CTRL MSR. > > A copy of this document is available at > https://bugzilla.kernel.org/show_bug.cgi?id=199889 > > Anyhow, this means that on future AMD CPUs there will be _two_ ways to > deal with SSBD. Does anybody know if there are AMD CPUs where virt-ssbd won't work and would require amd-ssbd to mitigate vulnerabilities? Also, do we have kernel arch/x86/kvm/cpuid.c patches, already? I prefer to add new CPUID flag names only after the flag name is already agreed upon on the kernel side. > > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > --- > target/i386/cpu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 52d334a..f91990c 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -490,7 +490,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = { > "ibpb", NULL, NULL, NULL, > NULL, NULL, NULL, NULL, > NULL, NULL, NULL, NULL, > - NULL, "virt-ssbd", NULL, NULL, > + "amd-ssbd", "virt-ssbd", NULL, NULL, > NULL, NULL, NULL, NULL, > }, > .cpuid_eax = 0x80000008, > -- > 1.8.3.1 > > -- Eduardo
