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Commit d1e5b0e9 authored by Marc Orr's avatar Marc Orr Committed by Paolo Bonzini
Browse files

kvm: Make VM ioctl do valloc for some archs 



The kvm struct has been bloating. For example, it's tens of kilo-bytes
for x86, which turns out to be a large amount of memory to allocate
contiguously via kzalloc. Thus, this patch does the following:
1. Uses architecture-specific routines to allocate the kvm struct via
   vzalloc for x86.
2. Switches arm to __KVM_HAVE_ARCH_VM_ALLOC so that it can use vzalloc
   when has_vhe() is true.

Other architectures continue to default to kalloc, as they have a
dependency on kalloc or have a small-enough struct kvm.

Signed-off-by: default avatarMarc Orr <marcorr@google.com>
Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1499fa80

arch/arm/include/asm/kvm_host.h

+4 −0
Original line number Diff line number Diff line
@@ -324,4 +324,8 @@ static inline bool kvm_arm_harden_branch_predictor(void) 
static inline void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) {}

static inline void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) {}



#define __KVM_HAVE_ARCH_VM_ALLOC

struct kvm *kvm_arch_alloc_vm(void);

void kvm_arch_free_vm(struct kvm *kvm);



#endif /* __ARM_KVM_HOST_H__ */

arch/arm64/include/asm/kvm_host.h

+4 −0
Original line number Diff line number Diff line
@@ -482,4 +482,8 @@ static inline bool kvm_arm_harden_branch_predictor(void) 
void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu);

void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu);



#define __KVM_HAVE_ARCH_VM_ALLOC

struct kvm *kvm_arch_alloc_vm(void);

void kvm_arch_free_vm(struct kvm *kvm);



#endif /* __ARM64_KVM_HOST_H__ */

arch/x86/kvm/svm.c

+2 −2
Original line number Diff line number Diff line
@@ -1852,13 +1852,13 @@ static void __unregister_enc_region_locked(struct kvm *kvm, 


static struct kvm *svm_vm_alloc(void)

{

	struct kvm_svm *kvm_svm = kzalloc(sizeof(struct kvm_svm), GFP_KERNEL);

	struct kvm_svm *kvm_svm = vzalloc(sizeof(struct kvm_svm));

	return &kvm_svm->kvm;

}



static void svm_vm_free(struct kvm *kvm)

{

	kfree(to_kvm_svm(kvm));

	vfree(to_kvm_svm(kvm));

}



static void sev_vm_destroy(struct kvm *kvm)

arch/x86/kvm/vmx.c

+2 −2
Original line number Diff line number Diff line
@@ -10139,13 +10139,13 @@ STACK_FRAME_NON_STANDARD(vmx_vcpu_run); 


static struct kvm *vmx_vm_alloc(void)

{

	struct kvm_vmx *kvm_vmx = kzalloc(sizeof(struct kvm_vmx), GFP_KERNEL);

	struct kvm_vmx *kvm_vmx = vzalloc(sizeof(struct kvm_vmx));

	return &kvm_vmx->kvm;

}



static void vmx_vm_free(struct kvm *kvm)

{

	kfree(to_kvm_vmx(kvm));

	vfree(to_kvm_vmx(kvm));

}



static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs)

include/linux/kvm_host.h

+5 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/preempt.h>

#include <linux/msi.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/rcupdate.h>

#include <linux/ratelimit.h>

#include <linux/err.h>
@@ -811,6 +812,10 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu); 
int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu);



#ifndef __KVM_HAVE_ARCH_VM_ALLOC

/*

 * All architectures that want to use vzalloc currently also

 * need their own kvm_arch_alloc_vm implementation.

 */

static inline struct kvm *kvm_arch_alloc_vm(void)

{

	return kzalloc(sizeof(struct kvm), GFP_KERNEL);