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Commit a983fb23 authored by Marcelo Tosatti's avatar Marcelo Tosatti
Browse files

KVM: x86: switch kvm_set_memory_alias to SRCU update 



Using a similar two-step procedure as for memslots.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent b050b015

arch/x86/include/asm/kvm_host.h

+4 −0
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/x86.c

+51 −9
Original line number Diff line number Diff line
@@ -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;

}

include/linux/kvm_host.h

+6 −0
Original line number Diff line number Diff line
@@ -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

virt/kvm/kvm_main.c

+2 −2
Original line number Diff line number Diff line
@@ -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();