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authorMarcelo Tosatti <mtosatti@redhat.com>2009-12-23 14:35:23 -0200
committerMarcelo Tosatti <mtosatti@redhat.com>2010-03-01 12:35:45 -0300
commita983fb238728e1123177e8058d4f644b949a7d05 (patch)
tree55f9b26d8ace10a1233b293dd423eae2d0ff9046 /arch
parentb050b015abbef8225826eecb6f6b4d4a6dea7b79 (diff)
KVM: x86: switch kvm_set_memory_alias to SRCU update
Using a similar two-step procedure as for memslots. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/kvm_host.h4
-rw-r--r--arch/x86/kvm/x86.c60
2 files changed, 55 insertions, 9 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7cdcb3d0f77..6c8c7c578c4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -368,8 +368,12 @@ struct kvm_mem_alias {
gfn_t base_gfn;
unsigned long npages;
gfn_t target_gfn;
+#define KVM_ALIAS_INVALID 1UL
+ unsigned long flags;
};
+#define KVM_ARCH_HAS_UNALIAS_INSTANTIATION
+
struct kvm_mem_aliases {
struct kvm_mem_alias aliases[KVM_ALIAS_SLOTS];
int naliases;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e7488350ca1..28127c936c3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -38,6 +38,7 @@
#include <linux/intel-iommu.h>
#include <linux/cpufreq.h>
#include <linux/user-return-notifier.h>
+#include <linux/srcu.h>
#include <trace/events/kvm.h>
#undef TRACE_INCLUDE_FILE
#define CREATE_TRACE_POINTS
@@ -2223,11 +2224,32 @@ static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm)
return kvm->arch.n_alloc_mmu_pages;
}
+gfn_t unalias_gfn_instantiation(struct kvm *kvm, gfn_t gfn)
+{
+ int i;
+ struct kvm_mem_alias *alias;
+ struct kvm_mem_aliases *aliases;
+
+ aliases = rcu_dereference(kvm->arch.aliases);
+
+ for (i = 0; i < aliases->naliases; ++i) {
+ alias = &aliases->aliases[i];
+ if (alias->flags & KVM_ALIAS_INVALID)
+ continue;
+ if (gfn >= alias->base_gfn
+ && gfn < alias->base_gfn + alias->npages)
+ return alias->target_gfn + gfn - alias->base_gfn;
+ }
+ return gfn;
+}
+
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
{
int i;
struct kvm_mem_alias *alias;
- struct kvm_mem_aliases *aliases = kvm->arch.aliases;
+ struct kvm_mem_aliases *aliases;
+
+ aliases = rcu_dereference(kvm->arch.aliases);
for (i = 0; i < aliases->naliases; ++i) {
alias = &aliases->aliases[i];
@@ -2248,7 +2270,7 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
{
int r, n;
struct kvm_mem_alias *p;
- struct kvm_mem_aliases *aliases;
+ struct kvm_mem_aliases *aliases, *old_aliases;
r = -EINVAL;
/* General sanity checks */
@@ -2265,28 +2287,48 @@ static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
< alias->target_phys_addr)
goto out;
+ r = -ENOMEM;
+ aliases = kzalloc(sizeof(struct kvm_mem_aliases), GFP_KERNEL);
+ if (!aliases)
+ goto out;
+
down_write(&kvm->slots_lock);
- spin_lock(&kvm->mmu_lock);
- aliases = kvm->arch.aliases;
+ /* invalidate any gfn reference in case of deletion/shrinking */
+ memcpy(aliases, kvm->arch.aliases, sizeof(struct kvm_mem_aliases));
+ aliases->aliases[alias->slot].flags |= KVM_ALIAS_INVALID;
+ old_aliases = kvm->arch.aliases;
+ rcu_assign_pointer(kvm->arch.aliases, aliases);
+ synchronize_srcu_expedited(&kvm->srcu);
+ kvm_mmu_zap_all(kvm);
+ kfree(old_aliases);
+
+ r = -ENOMEM;
+ aliases = kzalloc(sizeof(struct kvm_mem_aliases), GFP_KERNEL);
+ if (!aliases)
+ goto out_unlock;
+
+ memcpy(aliases, kvm->arch.aliases, sizeof(struct kvm_mem_aliases));
p = &aliases->aliases[alias->slot];
p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
p->npages = alias->memory_size >> PAGE_SHIFT;
p->target_gfn = alias->target_phys_addr >> PAGE_SHIFT;
+ p->flags &= ~(KVM_ALIAS_INVALID);
for (n = KVM_ALIAS_SLOTS; n > 0; --n)
if (aliases->aliases[n - 1].npages)
break;
aliases->naliases = n;
- spin_unlock(&kvm->mmu_lock);
- kvm_mmu_zap_all(kvm);
+ old_aliases = kvm->arch.aliases;
+ rcu_assign_pointer(kvm->arch.aliases, aliases);
+ synchronize_srcu_expedited(&kvm->srcu);
+ kfree(old_aliases);
+ r = 0;
+out_unlock:
up_write(&kvm->slots_lock);
-
- return 0;
-
out:
return r;
}