From 76da4cf6ec259ffa43b83af75e19cdf289e5731e Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Fri, 13 Apr 2018 15:42:34 +0000 Subject: [PATCH] x86/msr: Virtualise MSR_SPEC_CTRL.SSBD for guests to use Almost all infrastructure is already in place. Update the reserved bits calculation in guest_wrmsr(), and offer SSBD to guests by default. Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich --- xen/arch/x86/domctl.c | 3 ++- xen/arch/x86/hvm/hvm.c | 3 ++- xen/arch/x86/traps.c | 3 ++- xen/include/public/arch-x86/cpufeatureset.h | 2 +- 4 files changed, 7 insertions(+), 4 deletions(-) diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c index 1874949..47b8835 100644 --- a/xen/arch/x86/domctl.c +++ b/xen/arch/x86/domctl.c @@ -1408,7 +1408,8 @@ long arch_do_domctl( * ignored) when STIBP isn't enumerated in hardware. */ - if ( msr.value & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP) ) + if ( msr.value & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP | + (d->arch.cpuid->feat.ssbd ? SPEC_CTRL_SSBD : 0)) ) break; v->arch.spec_ctrl = msr.value; continue; diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 1a47ed9..de47c20 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -3619,7 +3619,8 @@ int hvm_msr_write_intercept(unsigned int msr, uint64_t msr_content, * when STIBP isn't enumerated in hardware. */ - if ( msr_content & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP) ) + if ( msr_content & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP | + (d->arch.cpuid->feat.ssbd ? SPEC_CTRL_SSBD : 0)) ) goto gp_fault; /* Rsvd bit set? */ v->arch.spec_ctrl = msr_content; diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c index b6add03..93b909c 100644 --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -2858,7 +2858,8 @@ static int priv_op_write_msr(unsigned int reg, uint64_t val, * when STIBP isn't enumerated in hardware. */ - if ( val & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP) ) + if ( val & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP | + (currd->arch.cpuid->feat.ssbd ? SPEC_CTRL_SSBD : 0)) ) break; /* Rsvd bit set? */ curr->arch.spec_ctrl = val; diff --git a/xen/include/public/arch-x86/cpufeatureset.h b/xen/include/public/arch-x86/cpufeatureset.h index 43f42b6..f2baea4 100644 --- a/xen/include/public/arch-x86/cpufeatureset.h +++ b/xen/include/public/arch-x86/cpufeatureset.h @@ -244,7 +244,7 @@ XEN_CPUFEATURE(AVX512_4FMAPS, 9*32+ 3) /*A AVX512 Multiply Accumulation Single XEN_CPUFEATURE(IBRSB, 9*32+26) /*A IBRS and IBPB support (used by Intel) */ XEN_CPUFEATURE(STIBP, 9*32+27) /*A! STIBP */ XEN_CPUFEATURE(ARCH_CAPS, 9*32+29) /* IA32_ARCH_CAPABILITIES MSR */ -XEN_CPUFEATURE(SSBD, 9*32+31) /* MSR_SPEC_CTRL.SSBD available */ +XEN_CPUFEATURE(SSBD, 9*32+31) /*A MSR_SPEC_CTRL.SSBD available */ #endif /* XEN_CPUFEATURE */ -- 2.1.4