[PATCH 17/23] KVM: MMU: remove redundant bits from extended role

Paolo Bonzini
2022-02-04T11:58:31Z

Before the separation of the CPU and the MMU role, CR0.PG was not
available in the base MMU role, because two-dimensional paging always
used direct=1 in the MMU role. However, now that the raw role is
snapshotted in mmu->cpu_role, CR0.PG *can* be found (though inverted)
as !cpu_role.base.direct. There is no need to store it again in union
kvm_mmu_extended_role; instead, write an is_cr0_pg accessor by hand that
takes care of the inversion.

Likewise, CR4.PAE is now always present in the CPU role as
!cpu_role.base.has_4_byte_gpte. The inversion makes certain tests on
the MMU role easier, and is easily hidden by the is_cr4_pae accessor
when operating on the CPU role.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 2 --
arch/x86/kvm/mmu/mmu.c | 14 ++++++++++----
2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 121eefdb9991..b0085c54786c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -360,8 +360,6 @@ union kvm_mmu_extended_role {
u32 word;
struct {
unsigned int execonly:1;
- unsigned int cr0_pg:1;
- unsigned int cr4_pae:1;
unsigned int cr4_pse:1;
unsigned int cr4_pke:1;
unsigned int cr4_smap:1;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0cb46a74e561..b3856551607d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -232,16 +232,24 @@ static inline bool __maybe_unused is_##reg##_##name(struct kvm_mmu *mmu) \
{ \
return !!(mmu->cpu_role. base_or_ext . reg##_##name); \
}
-BUILD_MMU_ROLE_ACCESSOR(ext, cr0, pg);
BUILD_MMU_ROLE_ACCESSOR(base, cr0, wp);
BUILD_MMU_ROLE_ACCESSOR(ext, cr4, pse);
-BUILD_MMU_ROLE_ACCESSOR(ext, cr4, pae);
BUILD_MMU_ROLE_ACCESSOR(ext, cr4, smep);
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);

+static inline bool is_cr0_pg(struct kvm_mmu *mmu)
+{
+ return !(mmu->cpu_role.base.direct);
+}
+
+static inline bool is_cr4_pae(struct kvm_mmu *mmu)
+{
+ return !(mmu->cpu_role.base.has_4_byte_gpte);
+}
+
static struct kvm_mmu_role_regs vcpu_to_role_regs(struct kvm_vcpu *vcpu)
{
struct kvm_mmu_role_regs regs = {
@@ -4668,8 +4676,6 @@ kvm_calc_cpu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
else
role.base.level = PT32_ROOT_LEVEL;

- 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);
--
2.31.1