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: Sean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-30-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 7f8184f432b498cdd3471383827940101135a193..a77cfc8bcf11f8c8959ddf9fd02918282da6211f 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -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);

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ff3f75105ae99860babf629b7acd0b492f5caf70..359c30be62bbd5693e8fa5aeb8a11db65ca60243 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -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);
 

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index db88ed4f2121c128936a6bc81d13072ea820b688..fd076bd26676c0ef58666a8dad98881065582ecd 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -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);