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Subject[PATCH v2 29/46] KVM: nVMX: Don't evaluate "emulation required" on nested VM-Exit
From
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>
---
arch/x86/kvm/vmx/nested.c | 16 ++++++++--------
arch/x86/kvm/vmx/vmx.c | 6 ++----
arch/x86/kvm/vmx/vmx.h | 2 +-
3 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 7f8184f432b4..a77cfc8bcf11 100644
--- 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 7ab493708b06..a1e5706fd27b 100644
--- 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 3979a947933a..b584e41bed44 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -373,7 +373,7 @@ 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);
--
2.32.0.93.g670b81a890-goog
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