Commit 816be9e9 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: nVMX: Don't evaluate "emulation required" on nested VM-Exit 



Use the "internal" variants of setting segment registers when stuffing
state on nested VM-Exit in order to skip the "emulation required"
updates.  VM-Exit must always go to protected mode, and all segments are
mostly hardcoded (to valid values) on VM-Exit.  The bits of the segments
that aren't hardcoded are explicitly checked during VM-Enter, e.g. the
selector RPLs must all be zero.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-30-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1dd7a4f1

arch/x86/kvm/vmx/nested.c

+8 −8
Original line number Diff line number Diff line
@@ -4267,7 +4267,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, 
		seg.l = 1;

	else

		seg.db = 1;

	vmx_set_segment(vcpu, &seg, VCPU_SREG_CS);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_CS);

	seg = (struct kvm_segment) {

		.base = 0,

		.limit = 0xFFFFFFFF,
@@ -4278,17 +4278,17 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, 
		.g = 1

	};

	seg.selector = vmcs12->host_ds_selector;

	vmx_set_segment(vcpu, &seg, VCPU_SREG_DS);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_DS);

	seg.selector = vmcs12->host_es_selector;

	vmx_set_segment(vcpu, &seg, VCPU_SREG_ES);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_ES);

	seg.selector = vmcs12->host_ss_selector;

	vmx_set_segment(vcpu, &seg, VCPU_SREG_SS);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_SS);

	seg.selector = vmcs12->host_fs_selector;

	seg.base = vmcs12->host_fs_base;

	vmx_set_segment(vcpu, &seg, VCPU_SREG_FS);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_FS);

	seg.selector = vmcs12->host_gs_selector;

	seg.base = vmcs12->host_gs_base;

	vmx_set_segment(vcpu, &seg, VCPU_SREG_GS);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_GS);

	seg = (struct kvm_segment) {

		.base = vmcs12->host_tr_base,

		.limit = 0x67,
@@ -4296,11 +4296,11 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, 
		.type = 11,

		.present = 1

	};

	vmx_set_segment(vcpu, &seg, VCPU_SREG_TR);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_TR);



	memset(&seg, 0, sizeof(seg));

	seg.unusable = 1;

	vmx_set_segment(vcpu, &seg, VCPU_SREG_LDTR);

	__vmx_set_segment(vcpu, &seg, VCPU_SREG_LDTR);



	kvm_set_dr(vcpu, 7, 0x400);

	vmcs_write64(GUEST_IA32_DEBUGCTL, 0);

arch/x86/kvm/vmx/vmx.c

+2 −4
Original line number Diff line number Diff line
@@ -2719,8 +2719,6 @@ static __init int alloc_kvm_area(void) 
	return 0;

}



static void __vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);



static void fix_pmode_seg(struct kvm_vcpu *vcpu, int seg,

		struct kvm_segment *save)

{
@@ -3293,7 +3291,7 @@ static u32 vmx_segment_access_rights(struct kvm_segment *var) 
	return ar;

}



static void __vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)

void __vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);

	const struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
@@ -3330,7 +3328,7 @@ static void __vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, in 
	vmcs_write32(sf->ar_bytes, vmx_segment_access_rights(var));

}



void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)

static void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)

{

	__vmx_set_segment(vcpu, var, seg);

arch/x86/kvm/vmx/vmx.h

+1 −1
Original line number Diff line number Diff line
@@ -371,7 +371,7 @@ void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4); 
void set_cr4_guest_host_mask(struct vcpu_vmx *vmx);

void ept_save_pdptrs(struct kvm_vcpu *vcpu);

void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);

void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);

void __vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);

u64 construct_eptp(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);



bool vmx_guest_inject_ac(struct kvm_vcpu *vcpu);