Add wrappers for setting regs_{avail,dirty} in anticipation of turning the fields into proper bitmaps, at which point direct writes won't work so well. Deliberately leave the initialization in kvm_arch_vcpu_create() as-is, because the regs_avail logic in particular is special in that it's the one and only place where KVM marks eagerly synchronized registers as available. No functional change intended. Signed-off-by: Sean Christopherson --- arch/x86/kvm/kvm_cache_regs.h | 18 ++++++++++++++++++ arch/x86/kvm/svm/svm.c | 4 ++-- arch/x86/kvm/vmx/nested.c | 4 ++-- arch/x86/kvm/vmx/tdx.c | 2 +- arch/x86/kvm/vmx/vmx.c | 4 ++-- 5 files changed, 25 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index ac1f9867a234..7f71d468178c 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -105,6 +105,24 @@ static __always_inline bool kvm_register_test_and_mark_available(struct kvm_vcpu return arch___test_and_set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail); } +static __always_inline void kvm_clear_available_registers(struct kvm_vcpu *vcpu, + u32 clear_mask) +{ + /* + * Note the bitwise-AND! In practice, a straight write would also work + * as KVM initializes the mask to all ones and never clears registers + * that are eagerly synchronized. Using a bitwise-AND adds a bit of + * sanity checking as incorrectly marking an eagerly sync'd register + * unavailable will generate a WARN due to an unexpected cache request. + */ + vcpu->arch.regs_avail &= ~clear_mask; +} + +static __always_inline void kvm_reset_dirty_registers(struct kvm_vcpu *vcpu) +{ + vcpu->arch.regs_dirty = 0; +} + /* * The "raw" register helpers are only for cases where the full 64 bits of a * register are read/written irrespective of current vCPU mode. In other words, diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ee5749d8b3e8..2b73d2650155 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4508,7 +4508,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags) vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp; vcpu->arch.rip = svm->vmcb->save.rip; } - vcpu->arch.regs_dirty = 0; + kvm_reset_dirty_registers(vcpu); if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI)) kvm_before_interrupt(vcpu, KVM_HANDLING_NMI); @@ -4554,7 +4554,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags) vcpu->arch.apf.host_apf_flags = kvm_read_and_reset_apf_flags(); - vcpu->arch.regs_avail &= ~SVM_REGS_LAZY_LOAD_SET; + kvm_clear_available_registers(vcpu, SVM_REGS_LAZY_LOAD_SET); if (!msr_write_intercepted(vcpu, MSR_AMD64_PERF_CNTR_GLOBAL_CTL)) rdmsrq(MSR_AMD64_PERF_CNTR_GLOBAL_CTL, vcpu_to_pmu(vcpu)->global_ctrl); diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 63c4ca8c97d5..c4d2bc080add 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -310,13 +310,13 @@ static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs) vmx_sync_vmcs_host_state(vmx, prev); put_cpu(); - vcpu->arch.regs_avail &= ~VMX_REGS_LAZY_LOAD_SET; + kvm_clear_available_registers(vcpu, VMX_REGS_LAZY_LOAD_SET); /* * All lazily updated registers will be reloaded from VMCS12 on both * vmentry and vmexit. */ - vcpu->arch.regs_dirty = 0; + kvm_reset_dirty_registers(vcpu); } static void nested_put_vmcs12_pages(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index c23ec4ac8bc8..c9ab7902151f 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1098,7 +1098,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags) tdx_load_host_xsave_state(vcpu); - vcpu->arch.regs_avail &= TDX_REGS_AVAIL_SET; + kvm_clear_available_registers(vcpu, ~(u32)TDX_REGS_AVAIL_SET); if (unlikely(tdx->vp_enter_ret == EXIT_REASON_EPT_MISCONFIG)) return EXIT_FASTPATH_NONE; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index aa1c26018439..61eeafcd70f1 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7472,7 +7472,7 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu, flags); vcpu->arch.cr2 = native_read_cr2(); - vcpu->arch.regs_avail &= ~VMX_REGS_LAZY_LOAD_SET; + kvm_clear_available_registers(vcpu, VMX_REGS_LAZY_LOAD_SET); vmx->idt_vectoring_info = 0; @@ -7538,7 +7538,7 @@ fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags) vmcs_writel(GUEST_RSP, vcpu->arch.regs[VCPU_REGS_RSP]); if (kvm_register_is_dirty(vcpu, VCPU_REG_RIP)) vmcs_writel(GUEST_RIP, vcpu->arch.rip); - vcpu->arch.regs_dirty = 0; + kvm_reset_dirty_registers(vcpu); if (run_flags & KVM_RUN_LOAD_GUEST_DR6) set_debugreg(vcpu->arch.dr6, 6); -- 2.53.0.1213.gd9a14994de-goog