On Fri, 03 Sep 2021 14:08:06 +0100,
Juergen Gross <jgross@xxxxxxxx> wrote:
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@xxxxxxxx>
---
V2:
- rebase to new kvm_arch_free_vm() implementation
---
arch/arm64/kvm/arm.c | 21 +++++++++++++++++++--
arch/x86/include/asm/kvm_host.h | 5 +----
arch/x86/kvm/x86.c | 18 ++++++++++++++++++
include/linux/kvm_host.h | 17 +++++++++++++++--
4 files changed, 53 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 38fff5963d9f..8bb5caeba007 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -293,10 +293,27 @@ long kvm_arch_dev_ioctl(struct file *filp,
struct kvm *kvm_arch_alloc_vm(void)
{
+ struct kvm *kvm;
+
+ if (!has_vhe())
+ kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);
+ else
+ kvm = vzalloc(sizeof(struct kvm));
+
+ if (!kvm)
+ return NULL;
+
if (!has_vhe())
- return kzalloc(sizeof(struct kvm), GFP_KERNEL);
+ 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 vzalloc(sizeof(struct kvm));
+ return 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 f16fadfc030a..6c28d0800208 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1517,10 +1517,7 @@ 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);
#define __KVM_HAVE_ARCH_VM_FREE
void kvm_arch_free_vm(struct kvm *kvm);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cc552763f0e4..ff142b6dd00c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11126,6 +11126,24 @@ 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);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d75e9c2a00b1..9e2a5f1c6f54 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -536,7 +536,7 @@ struct kvm {
struct mutex slots_arch_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;
At this stage, I really wonder why we are not using an xarray instead.
I wrote this [1] a while ago, and nothing caught fire. It was also a
net deletion of code...
Attachment:
OpenPGP_0xB0DE9DD628BF132F.asc
Description: OpenPGP public key
Attachment:
OpenPGP_signature
Description: OpenPGP digital signature