[PATCH v3 01/11] KVM: x86: Get active PCID only when writing a CR3 value

[Sean Christopherson]

Retrieve the active PCID only when writing a guest CR3 value, i.e. don't
get the PCID when using EPT.  The PCID is not used when EPT is enabled,
and must be manually stripped, which is annoying and unnecessary.
And on VMX, getting the active PCID also involves reading the guest's
CR3 and CR4.PCIDE, i.e. may add pointless VMREADs.

Opportunistically rename the pgd/pgd_level params to root_hpa and
root_level to better reflect their new roles.  Keep the function names,
as "load the guest PGD" is still accurate/correct.

Last, and probably least, pass root_hpa as a hpa_t/u64 instead of an
unsigned long.  The EPTP holds a 64-bit value, even in 32-bit mode, so
in theory EPT could support HIGHMEM for 32-bit KVM.  Never mind that
doing so would require changing the MMU page allocators and reworking
the MMU to use kmap().

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h |  4 ++--
 arch/x86/kvm/mmu.h              |  2 +-
 arch/x86/kvm/svm/svm.c          |  4 ++--
 arch/x86/kvm/vmx/vmx.c          | 13 ++++++-------
 arch/x86/kvm/vmx/vmx.h          |  3 +--
 5 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index d44858b69353..33b2acfd7869 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1181,8 +1181,8 @@ struct kvm_x86_ops {
 	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);
 
-	void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, unsigned long pgd,
-			     int pgd_level);
+	void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, hpa_t root_hpa,
+			     int root_level);
 
 	bool (*has_wbinvd_exit)(void);
 
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 9c4a9c8e43d9..add537a39177 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -95,7 +95,7 @@ static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu)
 	if (!VALID_PAGE(root_hpa))
 		return;
 
-	kvm_x86_ops.load_mmu_pgd(vcpu, root_hpa | kvm_get_active_pcid(vcpu),
+	kvm_x86_ops.load_mmu_pgd(vcpu, root_hpa,
 				 vcpu->arch.mmu->shadow_root_level);
 }
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index cf951e588dd1..4a6a5a3dc963 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3667,13 +3667,13 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 	return svm_exit_handlers_fastpath(vcpu);
 }
 
-static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root,
+static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
 			     int root_level)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	unsigned long cr3;
 
-	cr3 = __sme_set(root);
+	cr3 = __sme_set(root_hpa) | kvm_get_active_pcid(vcpu);
 	if (npt_enabled) {
 		svm->vmcb->control.nested_cr3 = cr3;
 		vmcb_mark_dirty(svm->vmcb, VMCB_NPT);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 281c405c7ea3..273a3206cef7 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3043,8 +3043,7 @@ static int vmx_get_max_tdp_level(void)
 	return 4;
 }
 
-u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa,
-		   int root_level)
+u64 construct_eptp(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level)
 {
 	u64 eptp = VMX_EPTP_MT_WB;
 
@@ -3053,13 +3052,13 @@ u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa,
 	if (enable_ept_ad_bits &&
 	    (!is_guest_mode(vcpu) || nested_ept_ad_enabled(vcpu)))
 		eptp |= VMX_EPTP_AD_ENABLE_BIT;
-	eptp |= (root_hpa & PAGE_MASK);
+	eptp |= root_hpa;
 
 	return eptp;
 }
 
-static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd,
-			     int pgd_level)
+static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
+			     int root_level)
 {
 	struct kvm *kvm = vcpu->kvm;
 	bool update_guest_cr3 = true;
@@ -3067,7 +3066,7 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd,
 	u64 eptp;
 
 	if (enable_ept) {
-		eptp = construct_eptp(vcpu, pgd, pgd_level);
+		eptp = construct_eptp(vcpu, root_hpa, root_level);
 		vmcs_write64(EPT_POINTER, eptp);
 
 		if (kvm_x86_ops.tlb_remote_flush) {
@@ -3086,7 +3085,7 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd,
 			update_guest_cr3 = false;
 		vmx_ept_load_pdptrs(vcpu);
 	} else {
-		guest_cr3 = pgd;
+		guest_cr3 = root_hpa | kvm_get_active_pcid(vcpu);
 	}
 
 	if (update_guest_cr3)
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index f6f66e5c6510..a2d143276603 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -326,8 +326,7 @@ 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,
-		   int root_level);
+u64 construct_eptp(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level);
 
 void update_exception_bitmap(struct kvm_vcpu *vcpu);
 void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);
-- 
2.28.0