[PATCH 30/45] KVM: Move vcpu alloc and init invocation to common code

Sean Christopherson
2019-10-22T01:59:10Z

Now that all architectures tightly couple vcpu allocation/free with the
mandatory calls to kvm_{un}init_vcpu(), move the sequences verbatim to
common KVM code.

Move both allocation and initialization in a single patch to eliminate
thrash in arch specific code. The bisection benefits of moving the two
pieces in separate patches is marginal at best, whereas the odds of
introducing a transient arch specific bug are non-zero.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/mips/kvm/mips.c | 33 ++++++---------------------------
arch/powerpc/kvm/powerpc.c | 27 ++++-----------------------
arch/s390/kvm/kvm-s390.c | 31 +++++--------------------------
arch/x86/kvm/x86.c | 28 ++--------------------------
include/linux/kvm_host.h | 2 +-
virt/kvm/arm/arm.c | 29 ++---------------------------
virt/kvm/kvm_main.c | 21 ++++++++++++++++++---
7 files changed, 38 insertions(+), 133 deletions(-)

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 8546bc6e09e7..92c9321b3f95 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -285,25 +285,14 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
return 0;
}

-struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
+int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
{
int err, size;
void *gebase, *p, *handler, *refill_start, *refill_end;
int i;

- struct kvm_vcpu *vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
-
- if (!vcpu) {
- err = -ENOMEM;
- goto out;
- }
-
- err = kvm_vcpu_init(vcpu, kvm, id);
-
- if (err)
- goto out_free_cpu;
-
- kvm_debug("kvm @ %p: create cpu %d at %p\n", kvm, id, vcpu);
+ kvm_debug("kvm @ %p: create cpu %d at %p\n",
+ vcpu->kvm, vcpu->vcpu_id, vcpu);

/*
* Allocate space for host mode exception handlers that handle
@@ -318,7 +307,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)

if (!gebase) {
err = -ENOMEM;
- goto out_uninit_cpu;
+ goto out;
}
kvm_debug("Allocated %d bytes for KVM Exception Handlers @ %p\n",
ALIGN(size, PAGE_SIZE), gebase);
@@ -397,19 +386,12 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
vcpu->arch.last_sched_cpu = -1;
vcpu->arch.last_exec_cpu = -1;

- return vcpu;
+ return 0;

out_free_gebase:
kfree(gebase);
-
-out_uninit_cpu:
- kvm_vcpu_uninit(vcpu);
-
-out_free_cpu:
- kmem_cache_free(kvm_vcpu_cache, vcpu);
-
out:
- return ERR_PTR(err);
+ return err;
}

void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
@@ -421,9 +403,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
kvm_mmu_free_memory_caches(vcpu);
kfree(vcpu->arch.guest_ebase);
kfree(vcpu->arch.kseg0_commpage);
-
- kvm_vcpu_uninit(vcpu);
- kmem_cache_free(kvm_vcpu_cache, vcpu);
}

int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 69a1a1c36909..b14e1314f020 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -721,32 +721,17 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
return 0;
}

-struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
+int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
{
- struct kvm_vcpu *vcpu;
int err;

- vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
- if (!vcpu)
- return ERR_PTR(-ENOMEM);
-
- err = kvm_vcpu_init(vcpu, kvm, id);
- if (err)
- goto free_vcpu;
-
err = kvmppc_core_vcpu_create(vcpu);
if (err)
- goto uninit_vcpu;
+ return err;

vcpu->arch.wqp = &vcpu->wq;
- kvmppc_create_vcpu_debugfs(vcpu, id);
- return vcpu;
-
-uninit_vcpu:
- kvm_vcpu_uninit(vcpu);
-free_vcpu:
- kmem_cache_free(kvm_vcpu_cache, vcpu);
- return ERR_PTR(err);
+ kvmppc_create_vcpu_debugfs(vcpu, vcpu->vcpu_id);
+ return 0;
}

void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
@@ -776,10 +761,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
}

kvmppc_core_vcpu_free(vcpu);
-
- kvm_vcpu_uninit(vcpu);
-
- kmem_cache_free(kvm_vcpu_cache, vcpu);
}

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 2c965f11c276..1e4f3b9ad031 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2533,9 +2533,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
if (vcpu->kvm->arch.use_cmma)
kvm_s390_vcpu_unsetup_cmma(vcpu);
free_page((unsigned long)(vcpu->arch.sie_block));
-
- kvm_vcpu_uninit(vcpu);
- kmem_cache_free(kvm_vcpu_cache, vcpu);
}

static void kvm_free_vcpus(struct kvm *kvm)
@@ -3017,29 +3014,15 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
return 0;
}

-struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
- unsigned int id)
+int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
{
- struct kvm_vcpu *vcpu;
struct sie_page *sie_page;
int rc;

- rc = -ENOMEM;
-
- vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
- if (!vcpu)
- goto out;
-
- rc = kvm_vcpu_init(vcpu, kvm, id);
- if (rc)
- goto out_free_cpu;
-
- rc = -ENOMEM;
-
BUILD_BUG_ON(sizeof(struct sie_page) != 4096);
sie_page = (struct sie_page *) get_zeroed_page(GFP_KERNEL);
if (!sie_page)
- goto out_uninit_vcpu;
+ return -ENOMEM;

vcpu->arch.sie_block = &sie_page->sie_block;
vcpu->arch.sie_block->itdba = (unsigned long) &sie_page->itdb;
@@ -3090,15 +3073,11 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
vcpu->arch.sie_block);
trace_kvm_s390_create_vcpu(id, vcpu, vcpu->arch.sie_block);

- return vcpu;
+ return 0;
+
out_free_sie_block:
free_page((unsigned long)(vcpu->arch.sie_block));
-out_uninit_vcpu:
- kvm_vcpu_uninit(vcpu);
-out_free_cpu:
- kmem_cache_free(kvm_vcpu_cache, vcpu);
-out:
- return ERR_PTR(rc);
+ return rc;
}

int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c72b104deaca..4d0cc3c9432f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9019,30 +9019,9 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
return 0;
}

-struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
- unsigned int id)
+int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
{
- struct kvm_vcpu *vcpu;
- int r;
-
- vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);
- if (!vcpu)
- return ERR_PTR(-ENOMEM);
-
- r = kvm_vcpu_init(vcpu, kvm, id);
- if (r)
- goto free_vcpu;
-
- r = kvm_x86_ops->vcpu_create(vcpu);
- if (r)
- goto uninit_vcpu;
- return vcpu;
-
-uninit_vcpu:
- kvm_vcpu_uninit(vcpu);
-free_vcpu:
- kmem_cache_free(kvm_vcpu_cache, vcpu);
- return ERR_PTR(r);
+ return kvm_x86_ops->vcpu_create(vcpu);
}

int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
@@ -9094,9 +9073,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);
kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu);
kmem_cache_free(x86_fpu_cache, vcpu->arch.guest_fpu);
-
- kvm_vcpu_uninit(vcpu);
- kmem_cache_free(kvm_vcpu_cache, vcpu);
}

void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f38d75f60c8c..8559d0448d0b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -857,7 +857,7 @@ void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu);
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu);
int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id);
-struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id);
+int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu);
int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index deb8a540538f..1ab151d43fd7 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -264,32 +264,9 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
return 0;
}

-struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
+int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
{
- int err;
- struct kvm_vcpu *vcpu;
-
- vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
- if (!vcpu) {
- err = -ENOMEM;
- goto out;
- }
-
- err = kvm_vcpu_init(vcpu, kvm, id);
- if (err)
- goto free_vcpu;
-
- err = create_hyp_mappings(vcpu, vcpu + 1, PAGE_HYP);
- if (err)
- goto vcpu_uninit;
-
- return vcpu;
-vcpu_uninit:
- kvm_vcpu_uninit(vcpu);
-free_vcpu:
- kmem_cache_free(kvm_vcpu_cache, vcpu);
-out:
- return ERR_PTR(err);
+ return create_hyp_mappings(vcpu, vcpu + 1, PAGE_HYP);
}

void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
@@ -304,8 +281,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
kvm_mmu_free_memory_caches(vcpu);
kvm_timer_vcpu_terminate(vcpu);
kvm_pmu_vcpu_destroy(vcpu);
- kvm_vcpu_uninit(vcpu);
- kmem_cache_free(kvm_vcpu_cache, vcpu);
}

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index dc6c721348dd..fb526bd55664 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -344,6 +344,9 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_uninit);
void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
kvm_arch_vcpu_destroy(vcpu);
+
+ kvm_vcpu_uninit(vcpu);
+ kmem_cache_free(kvm_vcpu_cache, vcpu);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_destroy);

@@ -2663,12 +2666,20 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
if (r)
goto vcpu_decrement;

- vcpu = kvm_arch_vcpu_create(kvm, id);
- if (IS_ERR(vcpu)) {
- r = PTR_ERR(vcpu);
+ vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
+ if (!vcpu) {
+ r = -ENOMEM;
goto vcpu_decrement;
}

+ r = kvm_vcpu_init(vcpu, kvm, id);
+ if (r)
+ goto vcpu_free;
+
+ r = kvm_arch_vcpu_create(vcpu);
+ if (r)
+ goto vcpu_uninit;
+
preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);

r = kvm_arch_vcpu_setup(vcpu);
@@ -2711,6 +2722,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
debugfs_remove_recursive(vcpu->debugfs_dentry);
vcpu_destroy:
kvm_arch_vcpu_destroy(vcpu);
+vcpu_uninit:
+ kvm_vcpu_uninit(vcpu);
+vcpu_free:
+ kmem_cache_free(kvm_vcpu_cache, vcpu);
vcpu_decrement:
mutex_lock(&kvm->lock);
kvm->created_vcpus--;
--
2.22.0