From 30031c2b0574f43cc6888532b715f639afd39196 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 29 Sep 2020 21:16:59 -0700 Subject: [PATCH] KVM: x86: Let the guest own CR4.FSGSBASE Add FSGSBASE to the set of possible guest-owned CR4 bits, i.e. let the guest own it on VMX. KVM never queries the guest's CR4.FSGSBASE value, thus there is no reason to force VM-Exit on FSGSBASE being toggled. Note, because FSGSBASE is conditionally available, this is dependent on recent changes to intercept reserved CR4 bits and to update the CR4 guest/host mask in response to guest CPUID changes. Cc: Paolo Bonzini Signed-off-by: Lai Jiangshan [sean: added justification in changelog] Signed-off-by: Sean Christopherson Message-Id: <20200930041659.28181-6-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/kvm_cache_regs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index ca0781b..a889563 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -7,7 +7,7 @@ #define KVM_POSSIBLE_CR0_GUEST_BITS X86_CR0_TS #define KVM_POSSIBLE_CR4_GUEST_BITS \ (X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR \ - | X86_CR4_OSXMMEXCPT | X86_CR4_PGE | X86_CR4_TSD) + | X86_CR4_OSXMMEXCPT | X86_CR4_PGE | X86_CR4_TSD | X86_CR4_FSGSBASE) #define BUILD_KVM_GPR_ACCESSORS(lname, uname) \ static __always_inline unsigned long kvm_##lname##_read(struct kvm_vcpu *vcpu)\ -- 2.7.4