From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: seanjc@google.com
Subject: [PATCH 18/22] KVM: x86/mmu: simplify and/or inline computation of shadow MMU roles
Date: Thu, 14 Apr 2022 03:39:56 -0400 [thread overview]
Message-ID: <20220414074000.31438-19-pbonzini@redhat.com> (raw)
In-Reply-To: <20220414074000.31438-1-pbonzini@redhat.com>
Shadow MMUs compute their role from cpu_role.base, simply by adjusting
the root level. It's one line of code, so do not place it in a separate
function.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/mmu/mmu.c | 65 ++++++++++++++++--------------------------
1 file changed, 24 insertions(+), 41 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 33827d1e3d5a..f22aa9970356 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -231,6 +231,7 @@ BUILD_MMU_ROLE_ACCESSOR(ext, cr4, smap);
BUILD_MMU_ROLE_ACCESSOR(ext, cr4, pke);
BUILD_MMU_ROLE_ACCESSOR(ext, cr4, la57);
BUILD_MMU_ROLE_ACCESSOR(base, efer, nx);
+BUILD_MMU_ROLE_ACCESSOR(ext, efer, lma);
static inline bool is_cr0_pg(struct kvm_mmu *mmu)
{
@@ -4796,33 +4797,6 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
reset_tdp_shadow_zero_bits_mask(context);
}
-static union kvm_mmu_page_role
-kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu,
- union kvm_cpu_role cpu_role)
-{
- union kvm_mmu_page_role role;
-
- role = cpu_role.base;
- if (!cpu_role.ext.efer_lma)
- role.level = PT32E_ROOT_LEVEL;
- else if (cpu_role.ext.cr4_la57)
- role.level = PT64_ROOT_5LEVEL;
- else
- role.level = PT64_ROOT_4LEVEL;
-
- /*
- * KVM forces EFER.NX=1 when TDP is disabled, reflect it in the MMU role.
- * KVM uses NX when TDP is disabled to handle a variety of scenarios,
- * notably for huge SPTEs if iTLB multi-hit mitigation is enabled and
- * to generate correct permissions for CR0.WP=0/CR4.SMEP=1/EFER.NX=0.
- * The iTLB multi-hit workaround can be toggled at any time, so assume
- * NX can be used by any non-nested shadow MMU to avoid having to reset
- * MMU contexts.
- */
- role.efer_nx = true;
- return role;
-}
-
static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
union kvm_cpu_role cpu_role,
union kvm_mmu_page_role root_role)
@@ -4853,22 +4827,25 @@ static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu,
{
struct kvm_mmu *context = &vcpu->arch.root_mmu;
union kvm_cpu_role cpu_role = kvm_calc_cpu_role(vcpu, regs);
- union kvm_mmu_page_role root_role =
- kvm_calc_shadow_mmu_root_page_role(vcpu, cpu_role);
+ union kvm_mmu_page_role root_role;
- shadow_mmu_init_context(vcpu, context, cpu_role, root_role);
-}
+ root_role = cpu_role.base;
-static union kvm_mmu_page_role
-kvm_calc_shadow_npt_root_page_role(struct kvm_vcpu *vcpu,
- union kvm_cpu_role cpu_role)
-{
- union kvm_mmu_page_role role;
+ /* KVM uses PAE paging whenever the guest isn't using 64-bit paging. */
+ root_role.level = max_t(u32, root_role.level, PT32E_ROOT_LEVEL);
- WARN_ON_ONCE(cpu_role.base.direct);
- role = cpu_role.base;
- role.level = kvm_mmu_get_tdp_level(vcpu);
- return role;
+ /*
+ * KVM forces EFER.NX=1 when TDP is disabled, reflect it in the MMU role.
+ * KVM uses NX when TDP is disabled to handle a variety of scenarios,
+ * notably for huge SPTEs if iTLB multi-hit mitigation is enabled and
+ * to generate correct permissions for CR0.WP=0/CR4.SMEP=1/EFER.NX=0.
+ * The iTLB multi-hit workaround can be toggled at any time, so assume
+ * NX can be used by any non-nested shadow MMU to avoid having to reset
+ * MMU contexts.
+ */
+ root_role.efer_nx = true;
+
+ shadow_mmu_init_context(vcpu, context, cpu_role, root_role);
}
void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
@@ -4881,7 +4858,13 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
.efer = efer,
};
union kvm_cpu_role cpu_role = kvm_calc_cpu_role(vcpu, ®s);
- union kvm_mmu_page_role root_role = kvm_calc_shadow_npt_root_page_role(vcpu, cpu_role);
+ union kvm_mmu_page_role root_role;
+
+ /* NPT requires CR0.PG=1. */
+ WARN_ON_ONCE(cpu_role.base.direct);
+
+ root_role = cpu_role.base;
+ root_role.level = kvm_mmu_get_tdp_level(vcpu);
shadow_mmu_init_context(vcpu, context, cpu_role, root_role);
kvm_mmu_new_pgd(vcpu, nested_cr3);
--
2.31.1
next prev parent reply other threads:[~2022-04-14 7:42 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 7:39 [PATCH v3 00/22] https://www.spinics.net/lists/kvm/msg267878.html Paolo Bonzini
2022-04-14 7:39 ` [PATCH 01/22] KVM: x86/mmu: nested EPT cannot be used in SMM Paolo Bonzini
2022-04-14 7:39 ` [PATCH 02/22] KVM: x86/mmu: constify uses of struct kvm_mmu_role_regs Paolo Bonzini
2022-04-14 7:39 ` [PATCH 03/22] KVM: x86/mmu: pull computation of kvm_mmu_role_regs to kvm_init_mmu Paolo Bonzini
2022-04-14 7:39 ` [PATCH 04/22] KVM: x86/mmu: rephrase unclear comment Paolo Bonzini
2022-04-14 7:39 ` [PATCH 05/22] KVM: x86: Clean up and document nested #PF workaround Paolo Bonzini
2022-04-14 7:39 ` [PATCH 06/22] KVM: x86/mmu: remove "bool base_only" arguments Paolo Bonzini
2022-04-14 7:39 ` [PATCH 07/22] KVM: x86/mmu: split cpu_role from mmu_role Paolo Bonzini
2022-04-15 4:16 ` Like Xu
2022-04-14 7:39 ` [PATCH 08/22] KVM: x86/mmu: do not recompute root level from kvm_mmu_role_regs Paolo Bonzini
2022-04-14 7:39 ` [PATCH 09/22] KVM: x86/mmu: remove ept_ad field Paolo Bonzini
2022-04-14 7:39 ` [PATCH 10/22] KVM: x86/mmu: remove kvm_calc_shadow_root_page_role_common Paolo Bonzini
2022-04-14 7:39 ` [PATCH 11/22] KVM: x86/mmu: cleanup computation of MMU roles for two-dimensional paging Paolo Bonzini
2022-04-14 7:39 ` [PATCH 12/22] KVM: x86/mmu: cleanup computation of MMU roles for shadow paging Paolo Bonzini
2022-04-14 7:39 ` [PATCH 13/22] KVM: x86/mmu: store shadow EFER.NX in the MMU role Paolo Bonzini
2022-04-14 7:39 ` [PATCH 14/22] KVM: x86/mmu: remove extended bits from mmu_role, rename field Paolo Bonzini
2022-04-14 7:39 ` [PATCH 15/22] KVM: x86/mmu: rename kvm_mmu_role union Paolo Bonzini
2022-04-14 7:39 ` [PATCH 16/22] KVM: x86/mmu: remove redundant bits from extended role Paolo Bonzini
2022-04-14 8:27 ` Paolo Bonzini
2022-05-10 0:20 ` Sean Christopherson
2022-05-11 13:53 ` Paolo Bonzini
2022-05-12 13:59 ` Paolo Bonzini
2022-05-12 14:18 ` Sean Christopherson
2022-05-12 16:09 ` Paolo Bonzini
2022-05-12 21:34 ` Sean Christopherson
2022-04-14 7:39 ` [PATCH 17/22] KVM: x86/mmu: remove valid " Paolo Bonzini
2022-04-14 7:39 ` Paolo Bonzini [this message]
2022-04-14 7:39 ` [PATCH 19/22] KVM: x86/mmu: pull CPU mode computation to kvm_init_mmu Paolo Bonzini
2022-04-14 7:39 ` [PATCH 20/22] KVM: x86/mmu: replace shadow_root_level with root_role.level Paolo Bonzini
2022-04-14 7:39 ` [PATCH 21/22] KVM: x86/mmu: replace root_level with cpu_role.base.level Paolo Bonzini
2022-04-14 7:40 ` [PATCH 22/22] KVM: x86/mmu: replace direct_map with root_role.direct Paolo Bonzini
2022-04-14 7:47 ` [PATCH v3 00/22] https://www.spinics.net/lists/kvm/msg267878.html Paolo Bonzini
2022-04-14 15:02 ` Sean Christopherson
2022-04-14 15:09 ` Paolo Bonzini
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