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Subject[PATCH 5/6] kvm: allocate vcpu pointer array separately
Date
Prepare support of very large vcpu numbers per guest by moving the
vcpu pointer array out of struct kvm.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/arm64/kvm/arm.c | 28 ++++++++++++++++++++++++----
arch/x86/include/asm/kvm_host.h | 5 +----
arch/x86/kvm/x86.c | 19 +++++++++++++++++++
include/linux/kvm_host.h | 17 +++++++++++++++--
4 files changed, 59 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e720148232a0..4f055408fe9f 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -280,18 +280,38 @@ long kvm_arch_dev_ioctl(struct file *filp,

struct kvm *kvm_arch_alloc_vm(void)
{
+ struct kvm *kvm;
+
if (!has_vhe())
- return kzalloc(sizeof(struct kvm), GFP_KERNEL);
+ kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);
+ else
+ kvm = vzalloc(sizeof(struct kvm));

- return vzalloc(sizeof(struct kvm));
+ if (!kvm)
+ return NULL;
+
+ if (!has_vhe())
+ kvm->vcpus = kcalloc(KVM_MAX_VCPUS, sizeof(void *), GFP_KERNEL);
+ else
+ kvm->vcpus = vzalloc(KVM_MAX_VCPUS * sizeof(void *));
+
+ if (!kvm->vcpus) {
+ kvm_arch_free_vm(kvm);
+ kvm = NULL;
+ }
+
+ return kvm;
}

void kvm_arch_free_vm(struct kvm *kvm)
{
- if (!has_vhe())
+ if (!has_vhe()) {
+ kfree(kvm->vcpus);
kfree(kvm);
- else
+ } else {
+ vfree(kvm->vcpus);
vfree(kvm);
+ }
}

int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 79138c91f83d..39cbc4b6bffb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1440,10 +1440,7 @@ static inline void kvm_ops_static_call_update(void)
}

#define __KVM_HAVE_ARCH_VM_ALLOC
-static inline struct kvm *kvm_arch_alloc_vm(void)
-{
- return __vmalloc(kvm_x86_ops.vm_size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
-}
+struct kvm *kvm_arch_alloc_vm(void);
void kvm_arch_free_vm(struct kvm *kvm);

#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLB
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3af398ef1fc9..a9b0bb2221ea 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10741,9 +10741,28 @@ void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu)
static_call(kvm_x86_sched_in)(vcpu, cpu);
}

+struct kvm *kvm_arch_alloc_vm(void)
+{
+ struct kvm *kvm;
+
+ kvm = __vmalloc(kvm_x86_ops.vm_size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+ if (!kvm)
+ return NULL;
+
+ kvm->vcpus = __vmalloc(KVM_MAX_VCPUS * sizeof(void *),
+ GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+ if (!kvm->vcpus) {
+ vfree(kvm);
+ kvm = NULL;
+ }
+
+ return kvm;
+}
+
void kvm_arch_free_vm(struct kvm *kvm)
{
kfree(to_kvm_hv(kvm)->hv_pa_pg);
+ vfree(kvm->vcpus);
vfree(kvm);
}

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 8583ed3ff344..e424ef1078a1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -525,7 +525,7 @@ struct kvm {
struct mutex slots_lock;
struct mm_struct *mm; /* userspace tied to this vm */
struct kvm_memslots __rcu *memslots[KVM_ADDRESS_SPACE_NUM];
- struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
+ struct kvm_vcpu **vcpus;

/*
* created_vcpus is protected by kvm->lock, and is incremented
@@ -1022,11 +1022,24 @@ void kvm_arch_pre_destroy_vm(struct kvm *kvm);
*/
static inline struct kvm *kvm_arch_alloc_vm(void)
{
- return kzalloc(sizeof(struct kvm), GFP_KERNEL);
+ struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);
+
+ if (!kvm)
+ return NULL;
+
+ kvm->vcpus = kcalloc(KVM_MAX_VCPUS, sizeof(void *), GFP_KERNEL);
+ if (!kvm->vcpus) {
+ kfree(kvm);
+ kvm = NULL;
+ }
+
+ return kvm;
}

static inline void kvm_arch_free_vm(struct kvm *kvm)
{
+ if (kvm)
+ kfree(kvm->vcpus);
kfree(kvm);
}
#endif
--
2.26.2
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