KVM: VMX: Add proper cache tracking for CR4

Move CR4 caching into the standard register caching mechanism in order
to take advantage of the availability checks provided by regs_avail.
This avoids multiple VMREADs and retpolines (when configured) during
nested VMX transitions as kvm_read_cr4_bits() is invoked multiple times
on each transition, e.g. when stuffing CR0 and CR3.

As an added bonus, this eliminates a kvm_x86_ops hook, saves a retpoline
on SVM when reading CR4, and squashes the confusing naming discrepancy
of "cache_reg" vs. "decache_cr4_guest_bits".

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200502043234.12481-7-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2020-05-01 21:32:30 -07:00
committed by Paolo Bonzini
parent 0cc69204e7
commit f98c1e7712
5 changed files with 14 additions and 17 deletions

View File

@@ -168,6 +168,7 @@ enum kvm_reg {
VCPU_EXREG_PDPTR = NR_VCPU_REGS,
VCPU_EXREG_CR3,
VCPU_EXREG_CR4,
VCPU_EXREG_RFLAGS,
VCPU_EXREG_SEGMENTS,
VCPU_EXREG_EXIT_INFO_1,
@@ -1092,7 +1093,6 @@ struct kvm_x86_ops {
struct kvm_segment *var, int seg);
void (*get_cs_db_l_bits)(struct kvm_vcpu *vcpu, int *db, int *l);
void (*decache_cr0_guest_bits)(struct kvm_vcpu *vcpu);
void (*decache_cr4_guest_bits)(struct kvm_vcpu *vcpu);
void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);
int (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4);
void (*set_efer)(struct kvm_vcpu *vcpu, u64 efer);