Commit ba28401b authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

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 bf07be36 ("KVM: x86: do not use KVM_X86_OP_OPTIONAL_RET0 for
get_mt_mask").

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20220714153707.3239119-1-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 277ad7d5

arch/x86/include/asm/kvm-x86-ops.h

+1 −1
Original line number Diff line number Diff line
@@ -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)

arch/x86/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/x86/kvm/svm/svm.c

+0 −6
Original line number Diff line number Diff line
@@ -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,

arch/x86/kvm/vmx/vmx.c

+1 −1
Original line number Diff line number Diff line
@@ -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;