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KVM: x86: switch kvm_set_memory_alias to SRCU update

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Using a similar two-step procedure as for memslots.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Marcelo Tosatti 2009-12-23 14:35:23 -02:00
parent b050b015ab
commit a983fb2387
4 changed files with 64 additions and 12 deletions
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4
arch/x86/include/asm/kvm_host.h
View File

@ -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;

62
arch/x86/kvm/x86.c
View File

@ -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;
down_write(&kvm->slots_lock);
spin_lock(&kvm->mmu_lock);
r = -ENOMEM;
aliases = kzalloc(sizeof(struct kvm_mem_aliases), GFP_KERNEL);
if (!aliases)
goto out;
aliases = kvm->arch.aliases;
down_write(&kvm->slots_lock);
/* 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;
}

6
include/linux/kvm_host.h
View File

@ -266,6 +266,8 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
void kvm_disable_largepages(void);
void kvm_arch_flush_shadow(struct kvm *kvm);
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);
gfn_t unalias_gfn_instantiation(struct kvm *kvm, gfn_t gfn);
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
void kvm_release_page_clean(struct page *page);
@ -539,6 +541,10 @@ static inline int mmu_notifier_retry(struct kvm_vcpu *vcpu, unsigned long mmu_se
}
#endif
#ifndef KVM_ARCH_HAS_UNALIAS_INSTANTIATION
#define unalias_gfn_instantiation unalias_gfn
#endif
#ifdef CONFIG_HAVE_KVM_IRQCHIP
#define KVM_MAX_IRQ_ROUTES 1024

4
virt/kvm/kvm_main.c
View File

@ -859,7 +859,7 @@ int kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
int i;
struct kvm_memslots *slots = rcu_dereference(kvm->memslots);
gfn = unalias_gfn(kvm, gfn);
gfn = unalias_gfn_instantiation(kvm, gfn);
for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
struct kvm_memory_slot *memslot = &slots->memslots[i];
@ -896,7 +896,7 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;
gfn = unalias_gfn(kvm, gfn);
gfn = unalias_gfn_instantiation(kvm, gfn);
slot = gfn_to_memslot_unaliased(kvm, gfn);
if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
return bad_hva();