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 allocat the kvm struct via
kzalloc for x86 and also for arm when has_tbe() is true.
2. Introduces a baseline allocator for the kvm struct that uses valloc.
This allocator can be used by an architecture by defining the
__KVM_VALLOC_ARCH_VM macro before including include/linux/kvm_host.h.
3. Finally, continue to default to kalloc for all other situations, as
many architectures have taken a dependence on kalloc.
Signed-off-by: Marc Orr <marcorr@xxxxxxxxxx>
Change-Id: Ide392e51991142d1325e06351231ac685e11d820
---
arch/arm/include/asm/kvm_host.h | 4 ++++
arch/arm64/include/asm/kvm_host.h | 4 ++++
arch/x86/kvm/svm.c | 4 ++--
arch/x86/kvm/vmx.c | 4 ++--
include/linux/kvm_host.h | 13 +++++++++++++
virt/kvm/arm/arm.c | 15 +++++++++++++++
6 files changed, 40 insertions(+), 4 deletions(-)
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index c7c28c885a19..f38fd60b4d4d 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -318,4 +318,8 @@ 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__ */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 469de8acd06f..358b1b4dcd92 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -455,4 +455,8 @@ 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__ */
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1fc05e428aba..45b903ed3e5d 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1849,13 +1849,13 @@ 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)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3f1696570b41..ee85ba887db6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9936,13 +9936,13 @@ 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)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 6d6e79c59e68..e3134283321a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -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>
@@ -808,6 +809,17 @@ 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
+#ifdef __KVM_VALLOC_ARCH_VM
+static inline struct kvm *kvm_arch_alloc_vm(void)
+{
+ return vzalloc(sizeof(struct kvm));
+}
+
+static inline void kvm_arch_free_vm(struct kvm *kvm)
+{
+ vfree(kvm);
+}
+#else
static inline struct kvm *kvm_arch_alloc_vm(void)
{
return kzalloc(sizeof(struct kvm), GFP_KERNEL);
@@ -818,6 +830,7 @@ static inline void kvm_arch_free_vm(struct kvm *kvm)
kfree(kvm);
}
#endif
+#endif
#ifdef __KVM_HAVE_ARCH_NONCOHERENT_DMA
void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index a4c1b76240df..ee96f18f852a 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -249,6 +249,21 @@ long kvm_arch_dev_ioctl(struct file *filp,
return -EINVAL;
}
+struct kvm *kvm_arch_alloc_vm(void)
+{
+ if (!has_vhe())
+ return kzalloc(sizeof(struct kvm), GFP_KERNEL);
+
+ return vzalloc(sizeof(struct kvm));
+}
+
+void kvm_arch_free_vm(struct kvm *kvm)
+{
+ if (!has_vhe())
+ kfree(kvm);
+ else
+ vfree(kvm);
+}
struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
{
--
2.17.0.441.gb46fe60e1d-goog
