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authorEugene Korenevsky <ekorenevsky@gmail.com>2015-03-29 23:56:12 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2015-04-08 10:46:56 +0200
commit5a4f55cde81f1633cb7ae9f0963b722e47acdc36 (patch)
tree8350e79b1b046374a5b4658dc498a3f8b1e8b8f5 /arch
parent80f0e95d1b221688b2608e0a80134e7acccd9a89 (diff)
downloadlinux-5a4f55cde81f1633cb7ae9f0963b722e47acdc36.tar.bz2
KVM: x86: cache maxphyaddr CPUID leaf in struct kvm_vcpu
cpuid_maxphyaddr(), which performs lot of memory accesses is called extensively across KVM, especially in nVMX code. This patch adds a cached value of maxphyaddr to vcpu.arch to reduce the pressure onto CPU cache and simplify the code of cpuid_maxphyaddr() callers. The cached value is initialized in kvm_arch_vcpu_init() and reloaded every time CPUID is updated by usermode. It is obvious that these reloads occur infrequently. Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com> Message-Id: <20150329205612.GA1223@gnote> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/kvm_host.h4
-rw-r--r--arch/x86/kvm/cpuid.c33
-rw-r--r--arch/x86/kvm/cpuid.h6
-rw-r--r--arch/x86/kvm/x86.c2
4 files changed, 29 insertions, 16 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 30b28dc76411..8d92e3bab118 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -426,6 +426,9 @@ struct kvm_vcpu_arch {
int cpuid_nent;
struct kvm_cpuid_entry2 cpuid_entries[KVM_MAX_CPUID_ENTRIES];
+
+ int maxphyaddr;
+
/* emulate context */
struct x86_emulate_ctxt emulate_ctxt;
@@ -1124,7 +1127,6 @@ int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end);
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
-int cpuid_maxphyaddr(struct kvm_vcpu *vcpu);
int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v);
int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu);
int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 8a80737ee6e6..59b69f6a2844 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -104,6 +104,9 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
((best->eax & 0xff00) >> 8) != 0)
return -EINVAL;
+ /* Update physical-address width */
+ vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
+
kvm_pmu_cpuid_update(vcpu);
return 0;
}
@@ -135,6 +138,21 @@ static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
}
}
+int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best;
+
+ best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
+ if (!best || best->eax < 0x80000008)
+ goto not_found;
+ best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
+ if (best)
+ return best->eax & 0xff;
+not_found:
+ return 36;
+}
+EXPORT_SYMBOL_GPL(cpuid_query_maxphyaddr);
+
/* when an old userspace process fills a new kernel module */
int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
struct kvm_cpuid *cpuid,
@@ -757,21 +775,6 @@ struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
}
EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
-int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
-{
- struct kvm_cpuid_entry2 *best;
-
- best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
- if (!best || best->eax < 0x80000008)
- goto not_found;
- best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
- if (best)
- return best->eax & 0xff;
-not_found:
- return 36;
-}
-EXPORT_SYMBOL_GPL(cpuid_maxphyaddr);
-
/*
* If no match is found, check whether we exceed the vCPU's limit
* and return the content of the highest valid _standard_ leaf instead.
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 26228466f3f8..c3b1ad9fca81 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -20,6 +20,12 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
struct kvm_cpuid_entry2 __user *entries);
void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
+int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu);
+
+static inline int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
+{
+ return vcpu->arch.maxphyaddr;
+}
static inline bool guest_cpuid_has_xsave(struct kvm_vcpu *vcpu)
{
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 50861dd15a94..a578629acb42 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7317,6 +7317,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
vcpu->arch.guest_supported_xcr0 = 0;
vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
+ vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
+
kvm_async_pf_hash_reset(vcpu);
kvm_pmu_init(vcpu);