[PATCH 26/28] KVM: SVM: enable GMET and set it in MMU role

[Paolo Bonzini]

Set the GMET bit in the nested control field.  This has effectively
no impact as long as NPT page tables are changed to have U=0.

Tested-by: David Riley <d.riley@xxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 arch/x86/kvm/mmu/mmu.c    |  6 +++++-
 arch/x86/kvm/svm/nested.c |  9 ++++++---
 arch/x86/kvm/svm/svm.c    | 16 ++++++++++++++++
 arch/x86/kvm/svm/svm.h    |  1 +
 4 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a283b5078c61..8b6122b66f06 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5855,7 +5855,6 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
 {
 	union kvm_mmu_page_role role = {0};
 
-	role.access = ACC_ALL;
 	role.cr0_wp = true;
 	role.cr4_smep = kvm_x86_call(tdp_has_smep)(vcpu->kvm);
 	role.efer_nx = true;
@@ -5866,6 +5865,11 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
 	role.direct = true;
 	role.has_4_byte_gpte = false;
 
+	/* All TDP pages are supervisor-executable */
+	role.access = ACC_ALL;
+	if (role.cr4_smep && shadow_user_mask)
+		role.access &= ~ACC_USER_MASK;
+
 	return role;
 }
 
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 7adfa7da210d..74a1df1cb84f 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -858,7 +858,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
 	 * the latter, L1 runs L2 with shadow page tables that translate L2 GVAs
 	 * to L1 GPAs, so the same NPTs can be used for L1 and L2.
 	 */
-	vmcb02->control.misc_ctl = vmcb01->control.misc_ctl & SVM_MISC_ENABLE_NP;
+	vmcb02->control.misc_ctl = vmcb01->control.misc_ctl & (SVM_MISC_ENABLE_NP | SVM_MISC_ENABLE_GMET);
 	vmcb02->control.iopm_base_pa = vmcb01->control.iopm_base_pa;
 	vmcb02->control.msrpm_base_pa = vmcb01->control.msrpm_base_pa;
 	vmcb_mark_dirty(vmcb02, VMCB_PERM_MAP);
@@ -895,9 +895,12 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
 	/* Also overwritten later if necessary.  */
 	vmcb02->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
 
-	/* nested_cr3.  */
-	if (nested_npt_enabled(svm))
+	/* Use vmcb01 MMU and format if guest does not use nNPT */
+	if (nested_npt_enabled(svm)) {
+		vmcb02->control.misc_ctl &= ~SVM_MISC_ENABLE_GMET;
+
 		nested_svm_init_mmu_context(vcpu);
+	}
 
 	vcpu->arch.tsc_offset = kvm_calc_nested_tsc_offset(vcpu->arch.l1_tsc_offset,
 							   vmcb12_ctrl->tsc_offset,
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e7fdd7a9c280..3895d8794366 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -138,6 +138,9 @@ module_param(pause_filter_count_max, ushort, 0444);
 bool __ro_after_init npt_enabled = true;
 module_param_named(npt, npt_enabled, bool, 0444);
 
+bool gmet_enabled = true;
+module_param_named(gmet, gmet_enabled, bool, 0444);
+
 /* allow nested virtualization in KVM/SVM */
 static int __ro_after_init nested = true;
 module_param(nested, int, 0444);
@@ -1209,6 +1212,10 @@ static void init_vmcb(struct kvm_vcpu *vcpu, bool init_event)
 		save->g_pat = vcpu->arch.pat;
 		save->cr3 = 0;
 	}
+
+	if (gmet_enabled)
+		control->misc_ctl |= SVM_MISC_ENABLE_GMET;
+
 	svm->current_vmcb->asid_generation = 0;
 	svm->asid = 0;
 
@@ -4612,6 +4619,11 @@ svm_patch_hypercall(struct kvm_vcpu *vcpu, unsigned char *hypercall)
 	hypercall[2] = 0xd9;
 }
 
+static bool svm_tdp_has_smep(struct kvm *kvm)
+{
+	return gmet_enabled;
+}
+
 /*
  * The kvm parameter can be NULL (module initialization, or invocation before
  * VM creation). Be sure to check the kvm parameter before using it.
@@ -5355,6 +5367,7 @@ struct kvm_x86_ops svm_x86_ops __initdata = {
 	.write_tsc_multiplier = svm_write_tsc_multiplier,
 
 	.load_mmu_pgd = svm_load_mmu_pgd,
+	.tdp_has_smep = svm_tdp_has_smep,
 
 	.check_intercept = svm_check_intercept,
 	.handle_exit_irqoff = svm_handle_exit_irqoff,
@@ -5588,6 +5601,9 @@ static __init int svm_hardware_setup(void)
 	if (!boot_cpu_has(X86_FEATURE_NPT))
 		npt_enabled = false;
 
+	if (!npt_enabled || !boot_cpu_has(X86_FEATURE_GMET))
+		gmet_enabled = false;
+
 	/* Force VM NPT level equal to the host's paging level */
 	kvm_configure_mmu(npt_enabled, get_npt_level(),
 			  get_npt_level(), PG_LEVEL_1G);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index a10668d17a16..dd93b3daefa9 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -44,6 +44,7 @@ static inline struct page *__sme_pa_to_page(unsigned long pa)
 #define	IOPM_SIZE PAGE_SIZE * 3
 #define	MSRPM_SIZE PAGE_SIZE * 2
 
+extern bool gmet_enabled;
 extern bool npt_enabled;
 extern int nrips;
 extern int vgif;
-- 
2.54.0