[PATCH v2 15/25] KVM: x86/mmu: remove extended bits from mmu_role, rename field

Paolo Bonzini
2022-02-21T16:24:14Z

mmu_role represents the role of the root of the page tables.
It does not need any extended bits, as those govern only KVM's
page table walking; the is_* functions used for page table
walking always use the CPU mode.

ext.valid is not present anymore in the MMU role, but an
all-zero MMU role is impossible because the level field is
never zero in the MMU role. So just zap the whole mmu_role
in order to force invalidation after CPUID is updated.

While making this change, which requires touching almost every
occurrence of "mmu_role", rename it to "root_role".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/mmu/mmu.c | 72 ++++++++++++++++-----------------
arch/x86/kvm/mmu/paging_tmpl.h | 4 +-
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
4 files changed, 39 insertions(+), 41 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 996cf9b14f5e..b7d7c4f31730 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -434,7 +434,7 @@ struct kvm_mmu {
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;
+ union kvm_mmu_page_role root_role;
u8 root_level;
u8 shadow_root_level;
bool direct_map;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index bbb5f50d3dcc..35907badb6ce 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -193,7 +193,7 @@ struct kvm_mmu_role_regs {

/*
* Yes, lot's of underscores. They're a hint that you probably shouldn't be
- * reading from the role_regs. Once the mmu_role is constructed, it becomes
+ * reading from the role_regs. Once the root_role is constructed, it becomes
* the single source of truth for the MMU's state.
*/
#define BUILD_MMU_ROLE_REGS_ACCESSOR(reg, name, flag) \
@@ -2029,7 +2029,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
int collisions = 0;
LIST_HEAD(invalid_list);

- role = vcpu->arch.mmu->mmu_role.base;
+ role = vcpu->arch.mmu->root_role;
role.level = level;
role.direct = direct;
role.access = access;
@@ -3265,7 +3265,7 @@ void kvm_mmu_free_guest_mode_roots(struct kvm *kvm, struct kvm_mmu *mmu)
* This should not be called while L2 is active, L2 can't invalidate
* _only_ its own roots, e.g. INVVPID unconditionally exits.
*/
- WARN_ON_ONCE(mmu->mmu_role.base.guest_mode);
+ WARN_ON_ONCE(mmu->root_role.guest_mode);

for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
root_hpa = mmu->prev_roots[i].hpa;
@@ -4158,7 +4158,7 @@ static bool fast_pgd_switch(struct kvm *kvm, struct kvm_mmu *mmu,
void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd)
{
struct kvm_mmu *mmu = vcpu->arch.mmu;
- union kvm_mmu_page_role new_role = mmu->mmu_role.base;
+ union kvm_mmu_page_role new_role = mmu->root_role;

if (!fast_pgd_switch(vcpu->kvm, mmu, new_pgd, new_role)) {
/* kvm_mmu_ensure_valid_pgd will set up a new root. */
@@ -4417,7 +4417,7 @@ static void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
shadow_zero_check = &context->shadow_zero_check;
__reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
context->shadow_root_level,
- context->mmu_role.base.efer_nx,
+ context->root_role.efer_nx,
guest_can_use_gbpages(vcpu), is_pse, is_amd);

if (!shadow_me_mask)
@@ -4710,22 +4710,21 @@ static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)
return max_tdp_level;
}

-static union kvm_mmu_role
+static union kvm_mmu_page_role
kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
union kvm_mmu_role cpu_mode)
{
- union kvm_mmu_role role = {0};
+ union kvm_mmu_page_role role = {0};

- role.base.access = ACC_ALL;
- role.base.cr0_wp = true;
- role.base.efer_nx = true;
- role.base.smm = cpu_mode.base.smm;
- role.base.guest_mode = cpu_mode.base.guest_mode;
- role.base.ad_disabled = (shadow_accessed_mask == 0);
- role.base.level = kvm_mmu_get_tdp_level(vcpu);
- role.base.direct = true;
- role.base.has_4_byte_gpte = false;
- role.ext.valid = true;
+ role.access = ACC_ALL;
+ role.cr0_wp = true;
+ role.efer_nx = true;
+ role.smm = cpu_mode.base.smm;
+ role.guest_mode = cpu_mode.base.guest_mode;
+ role.ad_disabled = (shadow_accessed_mask == 0);
+ role.level = kvm_mmu_get_tdp_level(vcpu);
+ role.direct = true;
+ role.has_4_byte_gpte = false;

return role;
}
@@ -4735,14 +4734,14 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
{
struct kvm_mmu *context = &vcpu->arch.root_mmu;
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, cpu_mode);
+ union kvm_mmu_page_role root_role = kvm_calc_tdp_mmu_root_page_role(vcpu, cpu_mode);

if (cpu_mode.as_u64 == context->cpu_mode.as_u64 &&
- mmu_role.as_u64 == context->mmu_role.as_u64)
+ root_role.word == context->root_role.word)
return;

context->cpu_mode.as_u64 = cpu_mode.as_u64;
- context->mmu_role.as_u64 = mmu_role.as_u64;
+ context->root_role.word = root_role.word;
context->page_fault = kvm_tdp_page_fault;
context->sync_page = nonpaging_sync_page;
context->invlpg = NULL;
@@ -4764,7 +4763,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
reset_tdp_shadow_zero_bits_mask(context);
}

-static union kvm_mmu_role
+static union kvm_mmu_page_role
kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu,
union kvm_mmu_role role)
{
@@ -4785,19 +4784,19 @@ kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu,
* MMU contexts.
*/
role.base.efer_nx = true;
- return role;
+ return role.base;
}

static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
union kvm_mmu_role cpu_mode,
- union kvm_mmu_role mmu_role)
+ union kvm_mmu_page_role root_role)
{
if (cpu_mode.as_u64 == context->cpu_mode.as_u64 &&
- mmu_role.as_u64 == context->mmu_role.as_u64)
+ root_role.word == context->root_role.word)
return;

context->cpu_mode.as_u64 = cpu_mode.as_u64;
- context->mmu_role.as_u64 = mmu_role.as_u64;
+ context->root_role.word = root_role.word;

if (!is_cr0_pg(context))
nonpaging_init_context(context);
@@ -4808,7 +4807,7 @@ static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *conte
context->root_level = cpu_mode.base.level;

reset_guest_paging_metadata(vcpu, context);
- context->shadow_root_level = mmu_role.base.level;
+ context->shadow_root_level = root_role.level;

reset_shadow_zero_bits_mask(vcpu, context);
}
@@ -4818,19 +4817,18 @@ static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu,
{
struct kvm_mmu *context = &vcpu->arch.root_mmu;
union kvm_mmu_role cpu_mode = kvm_calc_cpu_mode(vcpu, regs);
- union kvm_mmu_role mmu_role =
+ union kvm_mmu_page_role root_role =
kvm_calc_shadow_mmu_root_page_role(vcpu, cpu_mode);

- shadow_mmu_init_context(vcpu, context, cpu_mode, mmu_role);
+ shadow_mmu_init_context(vcpu, context, cpu_mode, root_role);
}

-static union kvm_mmu_role
+static union kvm_mmu_page_role
kvm_calc_shadow_npt_root_page_role(struct kvm_vcpu *vcpu,
union kvm_mmu_role role)
{
role.base.level = kvm_mmu_get_tdp_level(vcpu);
-
- return role;
+ return role.base;
}

void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
@@ -4843,9 +4841,9 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
.efer = efer,
};
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, cpu_mode);
+ union kvm_mmu_page_role root_role = kvm_calc_shadow_npt_root_page_role(vcpu, cpu_mode);

- shadow_mmu_init_context(vcpu, context, cpu_mode, mmu_role);
+ shadow_mmu_init_context(vcpu, context, cpu_mode, root_role);
kvm_mmu_new_pgd(vcpu, nested_cr3);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);
@@ -4888,7 +4886,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
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->root_role.word = new_mode.base.word;

context->shadow_root_level = level;

@@ -4987,9 +4985,9 @@ void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
* problem is swept under the rug; KVM's CPUID API is horrific and
* it's all but impossible to solve it without introducing a new API.
*/
- 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.root_role.word = 0;
+ vcpu->arch.guest_mmu.root_role.word = 0;
+ vcpu->arch.nested_mmu.root_role.word = 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;
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 64b6f76641f0..7c0fa115bd56 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -1023,7 +1023,7 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
*/
static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
{
- union kvm_mmu_page_role mmu_role = vcpu->arch.mmu->mmu_role.base;
+ union kvm_mmu_page_role root_role = vcpu->arch.mmu->root_role;
int i;
bool host_writable;
gpa_t first_pte_gpa;
@@ -1051,7 +1051,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
* reserved bits checks will be wrong, etc...
*/
if (WARN_ON_ONCE(sp->role.direct ||
- (sp->role.word ^ mmu_role.word) & ~sync_role_ign.word))
+ (sp->role.word ^ root_role.word) & ~sync_role_ign.word))
return -1;

first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index debf08212f12..c18ad86c9a82 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -209,7 +209,7 @@ static void tdp_mmu_init_child_sp(struct kvm_mmu_page *child_sp,

hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
{
- union kvm_mmu_page_role role = vcpu->arch.mmu->mmu_role.base;
+ union kvm_mmu_page_role role = vcpu->arch.mmu->root_role;
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_page *root;

--
2.31.1