KVM: x86: Pull the PGD's level from the MMU instead of recalculating it

Use the shadow_root_level from the current MMU as the root level for the
PGD, i.e. for VMX's EPTP.  This eliminates the weird dependency between
VMX and the MMU where both must independently calculate the same root
level for things to work correctly.  Temporarily keep VMX's calculation
of the level and use it to WARN if the incoming level diverges.

Opportunistically refactor kvm_mmu_load_pgd() to avoid indentation hell,
and rename a 'cr3' param in the load_mmu_pgd prototype that managed to
survive the cr3 purge.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200716034122.5998-6-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1bab87a444d781ffc66e494a13cf1cdacc66d90f..ce60f4c38843f7897244be1b9d7962736cf602e4 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1136,7 +1136,8 @@ struct kvm_x86_ops {
        int (*get_tdp_level)(struct kvm_vcpu *vcpu);
        u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
 
-       void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, unsigned long cr3);
+       void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, unsigned long pgd,
+                            int pgd_level);
 
        bool (*has_wbinvd_exit)(void);
 

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 9f6554613babc978373ad60ec62182a0415cca38..5efc6081ca138ed601e457041ba2cb12f96f6970 100644 (file)
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -90,9 +90,13 @@ static inline unsigned long kvm_get_active_pcid(struct kvm_vcpu *vcpu)
 
 static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu)
 {
-       if (VALID_PAGE(vcpu->arch.mmu->root_hpa))
-               kvm_x86_ops.load_mmu_pgd(vcpu, vcpu->arch.mmu->root_hpa |
-                                              kvm_get_active_pcid(vcpu));
+       u64 root_hpa = vcpu->arch.mmu->root_hpa;
+
+       if (!VALID_PAGE(root_hpa))
+               return;
+
+       kvm_x86_ops.load_mmu_pgd(vcpu, root_hpa | kvm_get_active_pcid(vcpu),
+                                vcpu->arch.mmu->shadow_root_level);
 }
 
 int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 783330d0e7b889678b6a86e933b4d746e6539f39..c70d7dd3330612a2e272a72f8deab9eea586b873 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3541,7 +3541,8 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
        return exit_fastpath;
 }
 
-static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root)
+static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root,
+                            int root_level)
 {
        struct vcpu_svm *svm = to_svm(vcpu);
        unsigned long cr3;

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4d561edf6f9ca6b1edf1e07f65603e0a313d4b21..e405e754b592be58c911bbe9cd16839f150cabc2 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2162,7 +2162,8 @@ static void prepare_vmcs02_constant_state(struct vcpu_vmx *vmx)
         * consistency checks.
         */
        if (enable_ept && nested_early_check)
-               vmcs_write64(EPT_POINTER, construct_eptp(&vmx->vcpu, 0));
+               vmcs_write64(EPT_POINTER,
+                            construct_eptp(&vmx->vcpu, 0, PT64_ROOT_4LEVEL));
 
        /* All VMFUNCs are currently emulated through L0 vmexits.  */
        if (cpu_has_vmx_vmfunc())

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 791baa73e5786ba60100b282f7c99fa752d9b0ee..244053cff0a3a9d7357938688348645b4b10997f 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2933,14 +2933,16 @@ static void vmx_flush_tlb_all(struct kvm_vcpu *vcpu)
 
 static void vmx_flush_tlb_current(struct kvm_vcpu *vcpu)
 {
-       u64 root_hpa = vcpu->arch.mmu->root_hpa;
+       struct kvm_mmu *mmu = vcpu->arch.mmu;
+       u64 root_hpa = mmu->root_hpa;
 
        /* No flush required if the current context is invalid. */
        if (!VALID_PAGE(root_hpa))
                return;
 
        if (enable_ept)
-               ept_sync_context(construct_eptp(vcpu, root_hpa));
+               ept_sync_context(construct_eptp(vcpu, root_hpa,
+                                               mmu->shadow_root_level));
        else if (!is_guest_mode(vcpu))
                vpid_sync_context(to_vmx(vcpu)->vpid);
        else
@@ -3078,11 +3080,12 @@ static int get_ept_level(struct kvm_vcpu *vcpu)
        return vmx_get_tdp_level(vcpu);
 }
 
-u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa)
+u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa,
+                  int root_level)
 {
        u64 eptp = VMX_EPTP_MT_WB;
 
-       eptp |= (get_ept_level(vcpu) == 5) ? VMX_EPTP_PWL_5 : VMX_EPTP_PWL_4;
+       eptp |= (root_level == 5) ? VMX_EPTP_PWL_5 : VMX_EPTP_PWL_4;
 
        if (enable_ept_ad_bits &&
            (!is_guest_mode(vcpu) || nested_ept_ad_enabled(vcpu)))
@@ -3092,7 +3095,8 @@ u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa)
        return eptp;
 }
 
-static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd)
+static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd,
+                            int pgd_level)
 {
        struct kvm *kvm = vcpu->kvm;
        bool update_guest_cr3 = true;
@@ -3100,7 +3104,9 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd)
        u64 eptp;
 
        if (enable_ept) {
-               eptp = construct_eptp(vcpu, pgd);
+               WARN_ON(pgd_level != get_ept_level(vcpu));
+
+               eptp = construct_eptp(vcpu, pgd, pgd_level);
                vmcs_write64(EPT_POINTER, eptp);
 
                if (kvm_x86_ops.tlb_remote_flush) {

diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 3c55433ac1b213eadb3a7a0c267b0aac3c353134..26175a4759fa5f8eef34b443dcb3fd6415b4f6b6 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -341,7 +341,8 @@ 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);
-u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa);
+u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa,
+                  int root_level);
 void update_exception_bitmap(struct kvm_vcpu *vcpu);
 void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);
 bool vmx_nmi_blocked(struct kvm_vcpu *vcpu);