[PATCH 28/40] KVM: split kvm_arch_set_memory_region into prepare and commit

From: Avi Kivity
Date: Wed Feb 10 2010 - 12:26:11 EST

From: Marcelo Tosatti <mtosatti@xxxxxxxxxx>

Required for SRCU convertion later.

Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
---
arch/ia64/kvm/kvm-ia64.c | 16 ++++++++++---
arch/powerpc/kvm/powerpc.c | 18 ++++++++++++---
arch/s390/kvm/kvm-s390.c | 25 +++++++++++++-------
arch/x86/kvm/x86.c | 51 +++++++++++++++++++++++++-------------------
include/linux/kvm_host.h | 7 +++++-
virt/kvm/kvm_main.c | 12 ++++------
6 files changed, 82 insertions(+), 47 deletions(-)

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 1ca1dbf..0757c70 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1578,15 +1578,15 @@ out:
return r;
}

-int kvm_arch_set_memory_region(struct kvm *kvm,
- struct kvm_userspace_memory_region *mem,
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+ struct kvm_memory_slot *memslot,
struct kvm_memory_slot old,
+ struct kvm_userspace_memory_region *mem,
int user_alloc)
{
unsigned long i;
unsigned long pfn;
- int npages = mem->memory_size >> PAGE_SHIFT;
- struct kvm_memory_slot *memslot = &kvm->memslots[mem->slot];
+ int npages = memslot->npages;
unsigned long base_gfn = memslot->base_gfn;

if (base_gfn + npages > (KVM_MAX_MEM_SIZE >> PAGE_SHIFT))
@@ -1610,6 +1610,14 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
return 0;
}

+void kvm_arch_commit_memory_region(struct kvm *kvm,
+ struct kvm_userspace_memory_region *mem,
+ struct kvm_memory_slot old,
+ int user_alloc)
+{
+ return;
+}
+
void kvm_arch_flush_shadow(struct kvm *kvm)
{
kvm_flush_remote_tlbs(kvm);
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index f06cf93..4633e78 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -165,14 +165,24 @@ long kvm_arch_dev_ioctl(struct file *filp,
return -EINVAL;
}

-int kvm_arch_set_memory_region(struct kvm *kvm,
- struct kvm_userspace_memory_region *mem,
- struct kvm_memory_slot old,
- int user_alloc)
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+ struct kvm_memory_slot *memslot,
+ struct kvm_memory_slot old,
+ struct kvm_userspace_memory_region *mem,
+ int user_alloc)
{
return 0;
}

+void kvm_arch_commit_memory_region(struct kvm *kvm,
+ struct kvm_userspace_memory_region *mem,
+ struct kvm_memory_slot old,
+ int user_alloc)
+{
+ return;
+}
+
+
void kvm_arch_flush_shadow(struct kvm *kvm)
{
}
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index f8bcaef..8bedd31 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -689,14 +689,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
}

/* Section: memory related */
-int kvm_arch_set_memory_region(struct kvm *kvm,
- struct kvm_userspace_memory_region *mem,
- struct kvm_memory_slot old,
- int user_alloc)
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+ struct kvm_memory_slot *memslot,
+ struct kvm_memory_slot old,
+ struct kvm_userspace_memory_region *mem,
+ int user_alloc)
{
- int i;
- struct kvm_vcpu *vcpu;
-
/* A few sanity checks. We can have exactly one memory slot which has
to start at guest virtual zero and which has to be located at a
page boundary in userland and which has to end at a page boundary.
@@ -719,14 +717,23 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
if (!user_alloc)
return -EINVAL;

+ return 0;
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+ struct kvm_userspace_memory_region *mem,
+ struct kvm_memory_slot old,
+ int user_alloc)
+{
+ int i;
+ struct kvm_vcpu *vcpu;
+
/* request update of sie control block for all available vcpus */
kvm_for_each_vcpu(i, vcpu, kvm) {
if (test_and_set_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
continue;
kvm_s390_inject_sigp_stop(vcpu, ACTION_RELOADVCPU_ON_STOP);
}
-
- return 0;
}

void kvm_arch_flush_shadow(struct kvm *kvm)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6a3593f..6a795be 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5229,13 +5229,13 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
kfree(kvm);
}

-int kvm_arch_set_memory_region(struct kvm *kvm,
- struct kvm_userspace_memory_region *mem,
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+ struct kvm_memory_slot *memslot,
struct kvm_memory_slot old,
+ struct kvm_userspace_memory_region *mem,
int user_alloc)
{
- int npages = mem->memory_size >> PAGE_SHIFT;
- struct kvm_memory_slot *memslot = &kvm->memslots->memslots[mem->slot];
+ int npages = memslot->npages;

/*To keep backward compatibility with older userspace,
*x86 needs to hanlde !user_alloc case.
@@ -5255,26 +5255,35 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
if (IS_ERR((void *)userspace_addr))
return PTR_ERR((void *)userspace_addr);

- /* set userspace_addr atomically for kvm_hva_to_rmapp */
- spin_lock(&kvm->mmu_lock);
memslot->userspace_addr = userspace_addr;
- spin_unlock(&kvm->mmu_lock);
- } else {
- if (!old.user_alloc && old.rmap) {
- int ret;
-
- down_write(&current->mm->mmap_sem);
- ret = do_munmap(current->mm, old.userspace_addr,
- old.npages * PAGE_SIZE);
- up_write(&current->mm->mmap_sem);
- if (ret < 0)
- printk(KERN_WARNING
- "kvm_vm_ioctl_set_memory_region: "
- "failed to munmap memory\n");
- }
}
}

+
+ return 0;
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+ struct kvm_userspace_memory_region *mem,
+ struct kvm_memory_slot old,
+ int user_alloc)
+{
+
+ int npages = mem->memory_size >> PAGE_SHIFT;
+
+ if (!user_alloc && !old.user_alloc && old.rmap && !npages) {
+ int ret;
+
+ down_write(&current->mm->mmap_sem);
+ ret = do_munmap(current->mm, old.userspace_addr,
+ old.npages * PAGE_SIZE);
+ up_write(&current->mm->mmap_sem);
+ if (ret < 0)
+ printk(KERN_WARNING
+ "kvm_vm_ioctl_set_memory_region: "
+ "failed to munmap memory\n");
+ }
+
spin_lock(&kvm->mmu_lock);
if (!kvm->arch.n_requested_mmu_pages) {
unsigned int nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
@@ -5283,8 +5292,6 @@ int kvm_arch_set_memory_region(struct kvm *kvm,

kvm_mmu_slot_remove_write_access(kvm, mem->slot);
spin_unlock(&kvm->mmu_lock);
-
- return 0;
}

void kvm_arch_flush_shadow(struct kvm *kvm)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 782bfb1..3c44687 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -253,7 +253,12 @@ int kvm_set_memory_region(struct kvm *kvm,
int __kvm_set_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem,
int user_alloc);
-int kvm_arch_set_memory_region(struct kvm *kvm,
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+ struct kvm_memory_slot *memslot,
+ struct kvm_memory_slot old,
+ struct kvm_userspace_memory_region *mem,
+ int user_alloc);
+void kvm_arch_commit_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem,
struct kvm_memory_slot old,
int user_alloc);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 86dd8f3..c9f6cfe 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -663,6 +663,10 @@ skip_lpage:
if (!npages)
kvm_arch_flush_shadow(kvm);

+ r = kvm_arch_prepare_memory_region(kvm, &new, old, mem, user_alloc);
+ if (r)
+ goto out_free;
+
spin_lock(&kvm->mmu_lock);
if (mem->slot >= kvm->memslots->nmemslots)
kvm->memslots->nmemslots = mem->slot + 1;
@@ -670,13 +674,7 @@ skip_lpage:
*memslot = new;
spin_unlock(&kvm->mmu_lock);

- r = kvm_arch_set_memory_region(kvm, mem, old, user_alloc);
- if (r) {
- spin_lock(&kvm->mmu_lock);
- *memslot = old;
- spin_unlock(&kvm->mmu_lock);
- goto out_free;
- }
+ kvm_arch_commit_memory_region(kvm, mem, old, user_alloc);

kvm_free_physmem_slot(&old, npages ? &new : NULL);
/* Slot deletion case: we have to update the current slot */
--
1.6.5.3

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