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kvm: vmx: Stop wasting a page for guest_msrs

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We will never need more guest_msrs than there are indices in
vmx_msr_index. Thus, at present, the guest_msrs array will not exceed
168 bytes.

Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jim Mattson 2019-12-03 16:24:42 -08:00 committed by Paolo Bonzini
parent 433f4ba190
commit 7d73710d9c
2 changed files with 9 additions and 11 deletions
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12
arch/x86/kvm/vmx/vmx.c
View File

@ -6674,7 +6674,6 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
free_vpid(vmx->vpid);
nested_vmx_free_vcpu(vcpu);
free_loaded_vmcs(vmx->loaded_vmcs);
kfree(vmx->guest_msrs);
kvm_vcpu_uninit(vcpu);
kmem_cache_free(x86_fpu_cache, vmx->vcpu.arch.user_fpu);
kmem_cache_free(x86_fpu_cache, vmx->vcpu.arch.guest_fpu);
@ -6731,12 +6730,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
goto uninit_vcpu;
}
vmx->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL_ACCOUNT);
BUILD_BUG_ON(ARRAY_SIZE(vmx_msr_index) * sizeof(vmx->guest_msrs[0])
> PAGE_SIZE);
if (!vmx->guest_msrs)
goto free_pml;
BUILD_BUG_ON(ARRAY_SIZE(vmx_msr_index) != NR_SHARED_MSRS);
for (i = 0; i < ARRAY_SIZE(vmx_msr_index); ++i) {
u32 index = vmx_msr_index[i];
@ -6768,7 +6762,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
err = alloc_loaded_vmcs(&vmx->vmcs01);
if (err < 0)
goto free_msrs;
goto free_pml;
msr_bitmap = vmx->vmcs01.msr_bitmap;
vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_TSC, MSR_TYPE_R);
@ -6830,8 +6824,6 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
free_vmcs:
free_loaded_vmcs(vmx->loaded_vmcs);
free_msrs:
kfree(vmx->guest_msrs);
free_pml:
vmx_destroy_pml_buffer(vmx);
uninit_vcpu:

8
arch/x86/kvm/vmx/vmx.h
View File

@ -22,6 +22,12 @@ extern u32 get_umwait_control_msr(void);
#define X2APIC_MSR(r) (APIC_BASE_MSR + ((r) >> 4))
#ifdef CONFIG_X86_64
#define NR_SHARED_MSRS 7
#else
#define NR_SHARED_MSRS 4
#endif
#define NR_LOADSTORE_MSRS 8
struct vmx_msrs {
@ -206,7 +212,7 @@ struct vcpu_vmx {
u32 idt_vectoring_info;
ulong rflags;
struct shared_msr_entry *guest_msrs;
struct shared_msr_entry guest_msrs[NR_SHARED_MSRS];
int nmsrs;
int save_nmsrs;
bool guest_msrs_ready;