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From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: dmatlack@google.com, seanjc@google.com
Subject: [PATCH v2 08/25] KVM: x86/mmu: split cpu_mode from mmu_role
Date: Mon, 21 Feb 2022 11:22:26 -0500	[thread overview]
Message-ID: <20220221162243.683208-9-pbonzini@redhat.com> (raw)
In-Reply-To: <20220221162243.683208-1-pbonzini@redhat.com>

Snapshot the state of the processor registers that govern page walk into
a new field of struct kvm_mmu.  This is a more natural representation
than having it *mostly* in mmu_role but not exclusively; the delta
right now is represented in other fields, such as root_level.

The nested MMU now has only the CPU mode; and in fact the new function
kvm_calc_cpu_mode is analogous to the previous kvm_calc_nested_mmu_role,
except that it has role.base.direct equal to CR0.PG.  It is not clear
what the code meant by "setting role.base.direct to true to detect bogus
usage of the nested MMU".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |   1 +
 arch/x86/kvm/mmu/mmu.c          | 107 ++++++++++++++++++++------------
 arch/x86/kvm/mmu/paging_tmpl.h  |   2 +-
 3 files changed, 68 insertions(+), 42 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 92855d3984a7..cc268116eb3f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -433,6 +433,7 @@ struct kvm_mmu {
 			 struct kvm_mmu_page *sp);
 	void (*invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa);
 	struct kvm_mmu_root_info root;
+	union kvm_mmu_role cpu_mode;
 	union kvm_mmu_role mmu_role;
 	u8 root_level;
 	u8 shadow_root_level;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 7c835253a330..1af898f0cf87 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -221,7 +221,7 @@ BUILD_MMU_ROLE_REGS_ACCESSOR(efer, lma, EFER_LMA);
 #define BUILD_MMU_ROLE_ACCESSOR(base_or_ext, reg, name)		\
 static inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu)	\
 {								\
-	return !!(mmu->mmu_role. base_or_ext . reg##_##name);	\
+	return !!(mmu->cpu_mode. base_or_ext . reg##_##name);	\
 }
 BUILD_MMU_ROLE_ACCESSOR(ext,  cr0, pg);
 BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
@@ -4680,6 +4680,39 @@ static void paging32_init_context(struct kvm_mmu *context)
 	context->direct_map = false;
 }
 
+static union kvm_mmu_role
+kvm_calc_cpu_mode(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
+{
+	union kvm_mmu_role role = {0};
+
+	role.base.access = ACC_ALL;
+	role.base.smm = is_smm(vcpu);
+	role.base.guest_mode = is_guest_mode(vcpu);
+	role.base.direct = !____is_cr0_pg(regs);
+	if (!role.base.direct) {
+		role.base.efer_nx = ____is_efer_nx(regs);
+		role.base.cr0_wp = ____is_cr0_wp(regs);
+		role.base.smep_andnot_wp = ____is_cr4_smep(regs) && !____is_cr0_wp(regs);
+		role.base.smap_andnot_wp = ____is_cr4_smap(regs) && !____is_cr0_wp(regs);
+		role.base.has_4_byte_gpte = !____is_cr4_pae(regs);
+		role.base.level = role_regs_to_root_level(regs);
+
+		role.ext.cr0_pg = 1;
+		role.ext.cr4_pae = ____is_cr4_pae(regs);
+		role.ext.cr4_smep = ____is_cr4_smep(regs);
+		role.ext.cr4_smap = ____is_cr4_smap(regs);
+		role.ext.cr4_pse = ____is_cr4_pse(regs);
+
+		/* PKEY and LA57 are active iff long mode is active. */
+		role.ext.cr4_pke = ____is_efer_lma(regs) && ____is_cr4_pke(regs);
+		role.ext.cr4_la57 = ____is_efer_lma(regs) && ____is_cr4_la57(regs);
+		role.ext.efer_lma = ____is_efer_lma(regs);
+	}
+
+	role.ext.valid = 1;
+	return role;
+}
+
 static union kvm_mmu_role kvm_calc_mmu_role_common(struct kvm_vcpu *vcpu,
 						   const struct kvm_mmu_role_regs *regs)
 {
@@ -4739,13 +4772,16 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
 			     const struct kvm_mmu_role_regs *regs)
 {
 	struct kvm_mmu *context = &vcpu->arch.root_mmu;
-	union kvm_mmu_role new_role =
+	union kvm_mmu_role cpu_mode = kvm_calc_cpu_mode(vcpu, regs);
+	union kvm_mmu_role mmu_role =
 		kvm_calc_tdp_mmu_root_page_role(vcpu, regs);
 
-	if (new_role.as_u64 == context->mmu_role.as_u64)
+	if (cpu_mode.as_u64 == context->cpu_mode.as_u64 &&
+	    mmu_role.as_u64 == context->mmu_role.as_u64)
 		return;
 
-	context->mmu_role.as_u64 = new_role.as_u64;
+	context->cpu_mode.as_u64 = cpu_mode.as_u64;
+	context->mmu_role.as_u64 = mmu_role.as_u64;
 	context->page_fault = kvm_tdp_page_fault;
 	context->sync_page = nonpaging_sync_page;
 	context->invlpg = NULL;
@@ -4800,13 +4836,15 @@ kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu,
 }
 
 static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
-				    const struct kvm_mmu_role_regs *regs,
-				    union kvm_mmu_role new_role)
+				    union kvm_mmu_role cpu_mode,
+				    union kvm_mmu_role mmu_role)
 {
-	if (new_role.as_u64 == context->mmu_role.as_u64)
+	if (cpu_mode.as_u64 == context->cpu_mode.as_u64 &&
+	    mmu_role.as_u64 == context->mmu_role.as_u64)
 		return;
 
-	context->mmu_role.as_u64 = new_role.as_u64;
+	context->cpu_mode.as_u64 = cpu_mode.as_u64;
+	context->mmu_role.as_u64 = mmu_role.as_u64;
 
 	if (!is_cr0_pg(context))
 		nonpaging_init_context(context);
@@ -4814,10 +4852,10 @@ static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *conte
 		paging64_init_context(context);
 	else
 		paging32_init_context(context);
-	context->root_level = role_regs_to_root_level(regs);
+	context->root_level = cpu_mode.base.level;
 
 	reset_guest_paging_metadata(vcpu, context);
-	context->shadow_root_level = new_role.base.level;
+	context->shadow_root_level = mmu_role.base.level;
 
 	reset_shadow_zero_bits_mask(vcpu, context);
 }
@@ -4826,10 +4864,11 @@ static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu,
 				const struct kvm_mmu_role_regs *regs)
 {
 	struct kvm_mmu *context = &vcpu->arch.root_mmu;
-	union kvm_mmu_role new_role =
+	union kvm_mmu_role cpu_mode = kvm_calc_cpu_mode(vcpu, regs);
+	union kvm_mmu_role mmu_role =
 		kvm_calc_shadow_mmu_root_page_role(vcpu, regs);
 
-	shadow_mmu_init_context(vcpu, context, regs, new_role);
+	shadow_mmu_init_context(vcpu, context, cpu_mode, mmu_role);
 }
 
 static union kvm_mmu_role
@@ -4854,11 +4893,10 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
 		.cr4 = cr4 & ~X86_CR4_PKE,
 		.efer = efer,
 	};
-	union kvm_mmu_role new_role;
+	union kvm_mmu_role cpu_mode = kvm_calc_cpu_mode(vcpu, &regs);
+	union kvm_mmu_role mmu_role = kvm_calc_shadow_npt_root_page_role(vcpu, &regs);;
 
-	new_role = kvm_calc_shadow_npt_root_page_role(vcpu, &regs);
-
-	shadow_mmu_init_context(vcpu, context, &regs, new_role);
+	shadow_mmu_init_context(vcpu, context, cpu_mode, mmu_role);
 	kvm_mmu_new_pgd(vcpu, nested_cr3);
 }
 EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
@@ -4881,7 +4919,6 @@ kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,
 	role.base.guest_mode = true;
 	role.base.access = ACC_ALL;
 
-	/* EPT, and thus nested EPT, does not consume CR0, CR4, nor EFER. */
 	role.ext.word = 0;
 	role.ext.execonly = execonly;
 	role.ext.valid = 1;
@@ -4895,12 +4932,14 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
 {
 	struct kvm_mmu *context = &vcpu->arch.guest_mmu;
 	u8 level = vmx_eptp_page_walk_level(new_eptp);
-	union kvm_mmu_role new_role =
+	union kvm_mmu_role new_mode =
 		kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
 						   execonly, level);
 
-	if (new_role.as_u64 != context->mmu_role.as_u64) {
-		context->mmu_role.as_u64 = new_role.as_u64;
+	if (new_mode.as_u64 != context->cpu_mode.as_u64) {
+		/* EPT, and thus nested EPT, does not consume CR0, CR4, nor EFER. */
+		context->cpu_mode.as_u64 = new_mode.as_u64;
+		context->mmu_role.as_u64 = new_mode.as_u64;
 
 		context->shadow_root_level = level;
 
@@ -4933,36 +4972,19 @@ static void init_kvm_softmmu(struct kvm_vcpu *vcpu,
 	context->inject_page_fault = kvm_inject_page_fault_shadow;
 }
 
-static union kvm_mmu_role
-kvm_calc_nested_mmu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
-{
-	union kvm_mmu_role role;
-
-	role = kvm_calc_shadow_root_page_role_common(vcpu, regs);
-
-	/*
-	 * Nested MMUs are used only for walking L2's gva->gpa, they never have
-	 * shadow pages of their own and so "direct" has no meaning.   Set it
-	 * to "true" to try to detect bogus usage of the nested MMU.
-	 */
-	role.base.direct = true;
-	role.base.level = role_regs_to_root_level(regs);
-	return role;
-}
-
 static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
 {
-	union kvm_mmu_role new_role = kvm_calc_nested_mmu_role(vcpu, regs);
+	union kvm_mmu_role new_mode = kvm_calc_cpu_mode(vcpu, regs);
 	struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
 
-	if (new_role.as_u64 == g_context->mmu_role.as_u64)
+	if (new_mode.as_u64 == g_context->cpu_mode.as_u64)
 		return;
 
-	g_context->mmu_role.as_u64 = new_role.as_u64;
+	g_context->cpu_mode.as_u64   = new_mode.as_u64;
 	g_context->get_guest_pgd     = kvm_get_guest_cr3;
 	g_context->get_pdptr         = kvm_pdptr_read;
 	g_context->inject_page_fault = kvm_inject_page_fault;
-	g_context->root_level        = new_role.base.level;
+	g_context->root_level        = new_mode.base.level;
 
 	/*
 	 * L2 page tables are never shadowed, so there is no need to sync
@@ -5020,6 +5042,9 @@ void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	vcpu->arch.root_mmu.mmu_role.ext.valid = 0;
 	vcpu->arch.guest_mmu.mmu_role.ext.valid = 0;
 	vcpu->arch.nested_mmu.mmu_role.ext.valid = 0;
+	vcpu->arch.root_mmu.cpu_mode.ext.valid = 0;
+	vcpu->arch.guest_mmu.cpu_mode.ext.valid = 0;
+	vcpu->arch.nested_mmu.cpu_mode.ext.valid = 0;
 	kvm_mmu_reset_context(vcpu);
 
 	/*
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index d1d17d28e81b..e1c2ecb4ddee 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -323,7 +323,7 @@ static inline bool FNAME(is_last_gpte)(struct kvm_mmu *mmu,
 	 * is not reserved and does not indicate a large page at this level,
 	 * so clear PT_PAGE_SIZE_MASK in gpte if that is the case.
 	 */
-	gpte &= level - (PT32_ROOT_LEVEL + mmu->mmu_role.ext.cr4_pse);
+	gpte &= level - (PT32_ROOT_LEVEL + mmu->cpu_mode.ext.cr4_pse);
 #endif
 	/*
 	 * PG_LEVEL_4K always terminates.  The RHS has bit 7 set
-- 
2.31.1



  parent reply	other threads:[~2022-02-21 16:23 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-21 16:22 [PATCH v2 00/25] KVM MMU refactoring part 2: role changes Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 01/25] KVM: x86/mmu: avoid indirect call for get_cr3 Paolo Bonzini
2022-03-08 16:16   ` Sean Christopherson
2022-03-08 16:21     ` Paolo Bonzini
2022-03-08 16:32       ` Sean Christopherson
2022-03-08 16:43         ` Paolo Bonzini
2022-03-08 16:53           ` Sean Christopherson
2022-03-08 17:14             ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 02/25] KVM: x86/mmu: nested EPT cannot be used in SMM Paolo Bonzini
2022-03-08 16:18   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 03/25] KVM: x86/mmu: constify uses of struct kvm_mmu_role_regs Paolo Bonzini
2022-03-08 16:22   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 04/25] KVM: x86/mmu: pull computation of kvm_mmu_role_regs to kvm_init_mmu Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 05/25] KVM: x86/mmu: rephrase unclear comment Paolo Bonzini
2022-03-08 16:39   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 06/25] KVM: nVMX/nSVM: do not monkey-patch inject_page_fault callback Paolo Bonzini
2022-03-08 17:13   ` Sean Christopherson
2022-03-08 20:34     ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 07/25] KVM: x86/mmu: remove "bool base_only" arguments Paolo Bonzini
2022-03-08 17:15   ` Sean Christopherson
2022-02-21 16:22 ` Paolo Bonzini [this message]
2022-03-08 17:36   ` [PATCH v2 08/25] KVM: x86/mmu: split cpu_mode from mmu_role Sean Christopherson
2022-03-08 17:49     ` Paolo Bonzini
2022-03-08 18:55   ` Sean Christopherson
2022-03-09  9:58     ` Paolo Bonzini
2022-03-09 15:38       ` Sean Christopherson
2022-03-09 15:40         ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 09/25] KVM: x86/mmu: do not recompute root level from kvm_mmu_role_regs Paolo Bonzini
2022-03-08 17:41   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 10/25] KVM: x86/mmu: remove ept_ad field Paolo Bonzini
2022-03-08 17:42   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 11/25] KVM: x86/mmu: remove kvm_calc_shadow_root_page_role_common Paolo Bonzini
2022-03-08 17:48   ` Sean Christopherson
2022-03-08 17:50     ` Paolo Bonzini
2022-03-08 18:17       ` Sean Christopherson
2022-03-08 18:18         ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 12/25] KVM: x86/mmu: cleanup computation of MMU roles for two-dimensional paging Paolo Bonzini
2022-03-08 18:11   ` Sean Christopherson
2022-03-08 18:24     ` Paolo Bonzini
2022-03-08 18:44       ` Sean Christopherson
2022-03-08 18:38     ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 13/25] KVM: x86/mmu: cleanup computation of MMU roles for shadow paging Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 14/25] KVM: x86/mmu: store shadow EFER.NX in the MMU role Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 15/25] KVM: x86/mmu: remove extended bits from mmu_role, rename field Paolo Bonzini
2022-03-08 19:02   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 16/25] KVM: x86/mmu: rename kvm_mmu_role union Paolo Bonzini
2022-03-08 19:15   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 17/25] KVM: x86/mmu: remove redundant bits from extended role Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 18/25] KVM: x86/mmu: remove valid " Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 19/25] KVM: x86/mmu: simplify and/or inline computation of shadow MMU roles Paolo Bonzini
2022-03-08 19:35   ` Sean Christopherson
2022-03-08 19:41     ` Sean Christopherson
2022-03-09 10:33     ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 20/25] KVM: x86/mmu: pull CPU mode computation to kvm_init_mmu Paolo Bonzini
2022-03-08 19:45   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 21/25] KVM: x86/mmu: replace shadow_root_level with root_role.level Paolo Bonzini
2022-03-08 19:48   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 22/25] KVM: x86/mmu: replace root_level with cpu_mode.base.level Paolo Bonzini
2022-03-08 19:49   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 23/25] KVM: x86/mmu: replace direct_map with root_role.direct Paolo Bonzini
2022-03-08 19:52   ` Sean Christopherson
2022-02-21 16:22 ` [PATCH v2 24/25] KVM: x86/mmu: initialize constant-value fields just once Paolo Bonzini
2022-03-08 20:58   ` Sean Christopherson
2022-03-09 10:34     ` Paolo Bonzini
2022-02-21 16:22 ` [PATCH v2 25/25] KVM: x86/mmu: extract initialization of the page walking data Paolo Bonzini
2022-03-08 20:02   ` Sean Christopherson

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