From ba28401bb93e5c779d5762c4eb0eb665493e5dd4 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 14 Jul 2022 15:37:07 +0000 Subject: [PATCH] KVM: x86: Restrict get_mt_mask() to a u8, use KVM_X86_OP_OPTIONAL_RET0 Restrict get_mt_mask() to a u8 and reintroduce using a RET0 static_call for the SVM implementation. EPT stores the memtype information in the lower 8 bits (bits 6:3 to be precise), and even returns a shifted u8 without an explicit cast to a larger type; there's no need to return a full u64. Note, RET0 doesn't play nice with a u64 return on 32-bit kernels, see commit bf07be36cd88 ("KVM: x86: do not use KVM_X86_OP_OPTIONAL_RET0 for get_mt_mask"). Signed-off-by: Sean Christopherson Message-Id: <20220714153707.3239119-1-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm-x86-ops.h | 2 +- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/svm/svm.c | 6 ------ arch/x86/kvm/vmx/vmx.c | 2 +- 4 files changed, 3 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h index 6f2f1af..51f7770 100644 --- a/arch/x86/include/asm/kvm-x86-ops.h +++ b/arch/x86/include/asm/kvm-x86-ops.h @@ -88,7 +88,7 @@ KVM_X86_OP(deliver_interrupt) KVM_X86_OP_OPTIONAL(sync_pir_to_irr) KVM_X86_OP_OPTIONAL_RET0(set_tss_addr) KVM_X86_OP_OPTIONAL_RET0(set_identity_map_addr) -KVM_X86_OP(get_mt_mask) +KVM_X86_OP_OPTIONAL_RET0(get_mt_mask) KVM_X86_OP(load_mmu_pgd) KVM_X86_OP(has_wbinvd_exit) KVM_X86_OP(get_l2_tsc_offset) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index d4ece7b..e8281d6 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1545,7 +1545,7 @@ struct kvm_x86_ops { int (*sync_pir_to_irr)(struct kvm_vcpu *vcpu); int (*set_tss_addr)(struct kvm *kvm, unsigned int addr); int (*set_identity_map_addr)(struct kvm *kvm, u64 ident_addr); - u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio); + u8 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio); void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 84414ea..ba81a7e 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4159,11 +4159,6 @@ static bool svm_has_emulated_msr(struct kvm *kvm, u32 index) return true; } -static u64 svm_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) -{ - return 0; -} - static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); @@ -4815,7 +4810,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .check_apicv_inhibit_reasons = avic_check_apicv_inhibit_reasons, .apicv_post_state_restore = avic_apicv_post_state_restore, - .get_mt_mask = svm_get_mt_mask, .get_exit_info = svm_get_exit_info, .vcpu_after_set_cpuid = svm_vcpu_after_set_cpuid, diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index e6ab2c2..b0cc911a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7354,7 +7354,7 @@ static int __init vmx_check_processor_compat(void) return 0; } -static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) +static u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) { u8 cache; -- 2.7.4