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Subject[PATCH v2 8/8] KVM: x86: Fold decache_cr3() into cache_reg()
Date
Handle caching CR3 (from VMX's VMCS) into struct kvm_vcpu via the common
cache_reg() callback and drop the dedicated decache_cr3(). The name
decache_cr3() is somewhat confusing as the caching behavior of CR3
follows that of GPRs, RFLAGS and PDPTRs, (handled via cache_reg()), and
has nothing in common with the caching behavior of CR0/CR4 (whose
decache_cr{0,4}_guest_bits() likely provided the 'decache' verbiage).

Note, this effectively adds a BUG() if KVM attempts to cache CR3 on SVM.
Opportunistically add a WARN_ON_ONCE() in VMX to provide an equivalent
check.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/asm/kvm_host.h | 1 -
arch/x86/kvm/kvm_cache_regs.h | 2 +-
arch/x86/kvm/svm.c | 5 -----
arch/x86/kvm/vmx/vmx.c | 15 ++++++---------
4 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a27f7f6b6b7a..0411dc0a27b0 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1040,7 +1040,6 @@ 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_cr3)(struct kvm_vcpu *vcpu);
void (*decache_cr4_guest_bits)(struct kvm_vcpu *vcpu);
void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0);
void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index 9c2bc528800b..f18177cd0030 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -145,7 +145,7 @@ static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask)
static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu)
{
if (!kvm_register_is_available(vcpu, VCPU_EXREG_CR3))
- kvm_x86_ops->decache_cr3(vcpu);
+ kvm_x86_ops->cache_reg(vcpu, VCPU_EXREG_CR3);
return vcpu->arch.cr3;
}

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f8ecb6df5106..3102c44c12c6 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2517,10 +2517,6 @@ static void svm_decache_cr0_guest_bits(struct kvm_vcpu *vcpu)
{
}

-static void svm_decache_cr3(struct kvm_vcpu *vcpu)
-{
-}
-
static void svm_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
{
}
@@ -7208,7 +7204,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.get_cpl = svm_get_cpl,
.get_cs_db_l_bits = kvm_get_cs_db_l_bits,
.decache_cr0_guest_bits = svm_decache_cr0_guest_bits,
- .decache_cr3 = svm_decache_cr3,
.decache_cr4_guest_bits = svm_decache_cr4_guest_bits,
.set_cr0 = svm_set_cr0,
.set_cr3 = svm_set_cr3,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index ed03d0cd1cc8..c84798026e85 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2188,7 +2188,12 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
if (enable_ept)
ept_save_pdptrs(vcpu);
break;
+ case VCPU_EXREG_CR3:
+ if (enable_unrestricted_guest || (enable_ept && is_paging(vcpu)))
+ vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
+ break;
default:
+ WARN_ON_ONCE(1);
break;
}
}
@@ -2859,13 +2864,6 @@ static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu)
vcpu->arch.cr0 |= vmcs_readl(GUEST_CR0) & cr0_guest_owned_bits;
}

-static void vmx_decache_cr3(struct kvm_vcpu *vcpu)
-{
- if (enable_unrestricted_guest || (enable_ept && is_paging(vcpu)))
- vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
- kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
-}
-
static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
{
ulong cr4_guest_owned_bits = vcpu->arch.cr4_guest_owned_bits;
@@ -2910,7 +2908,7 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
struct vcpu_vmx *vmx = to_vmx(vcpu);

if (!kvm_register_is_available(vcpu, VCPU_EXREG_CR3))
- vmx_decache_cr3(vcpu);
+ vmx_cache_reg(vcpu, VCPU_EXREG_CR3);
if (!(cr0 & X86_CR0_PG)) {
/* From paging/starting to nonpaging */
exec_controls_setbit(vmx, CPU_BASED_CR3_LOAD_EXITING |
@@ -7792,7 +7790,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
.get_cpl = vmx_get_cpl,
.get_cs_db_l_bits = vmx_get_cs_db_l_bits,
.decache_cr0_guest_bits = vmx_decache_cr0_guest_bits,
- .decache_cr3 = vmx_decache_cr3,
.decache_cr4_guest_bits = vmx_decache_cr4_guest_bits,
.set_cr0 = vmx_set_cr0,
.set_cr3 = vmx_set_cr3,
--
2.22.0
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