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Message-Id: <1199630379-28638-31-git-send-email-avi@qumranet.com>
Date: Sun, 6 Jan 2008 16:39:36 +0200
From: Avi Kivity <avi@...ranet.com>
To: linux-kernel@...r.kernel.org, kvm-devel@...ts.sourceforge.net
Cc: Marcelo Tosatti <mtosatti@...hat.com>
Subject: [PATCH 30/33] KVM: MMU: Switch to mmu spinlock
From: Marcelo Tosatti <mtosatti@...hat.com>
Convert the synchronization of the shadow handling to a separate mmu_lock
spinlock.
Also guard fetch() by mmap_sem in read-mode to protect against alias
and memslot changes.
Signed-off-by: Marcelo Tosatti <mtosatti@...hat.com>
Signed-off-by: Avi Kivity <avi@...ranet.com>
---
arch/x86/kvm/mmu.c | 48 +++++++++++++++++++++++--------------------
arch/x86/kvm/paging_tmpl.h | 10 +++++---
arch/x86/kvm/vmx.c | 2 -
include/linux/kvm_host.h | 3 +-
virt/kvm/kvm_main.c | 3 +-
5 files changed, 35 insertions(+), 31 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index c0b757b..834698d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -971,16 +971,12 @@ static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
{
}
-static int __nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
+static int __nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write,
+ gfn_t gfn, struct page *page)
{
int level = PT32E_ROOT_LEVEL;
hpa_t table_addr = vcpu->arch.mmu.root_hpa;
int pt_write = 0;
- struct page *page;
-
- down_read(¤t->mm->mmap_sem);
- page = gfn_to_page(vcpu->kvm, gfn);
- up_read(¤t->mm->mmap_sem);
for (; ; level--) {
u32 index = PT64_INDEX(v, level);
@@ -1022,9 +1018,17 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
{
int r;
- mutex_lock(&vcpu->kvm->lock);
- r = __nonpaging_map(vcpu, v, write, gfn);
- mutex_unlock(&vcpu->kvm->lock);
+ struct page *page;
+
+ down_read(¤t->mm->mmap_sem);
+ page = gfn_to_page(vcpu->kvm, gfn);
+
+ spin_lock(&vcpu->kvm->mmu_lock);
+ r = __nonpaging_map(vcpu, v, write, gfn, page);
+ spin_unlock(&vcpu->kvm->mmu_lock);
+
+ up_read(¤t->mm->mmap_sem);
+
return r;
}
@@ -1045,7 +1049,7 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
return;
- mutex_lock(&vcpu->kvm->lock);
+ spin_lock(&vcpu->kvm->mmu_lock);
#ifdef CONFIG_X86_64
if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
hpa_t root = vcpu->arch.mmu.root_hpa;
@@ -1053,7 +1057,7 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
sp = page_header(root);
--sp->root_count;
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
return;
}
#endif
@@ -1067,7 +1071,7 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
}
vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
}
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.root_hpa = INVALID_PAGE;
}
@@ -1270,9 +1274,9 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
r = mmu_topup_memory_caches(vcpu);
if (r)
goto out;
- mutex_lock(&vcpu->kvm->lock);
+ spin_lock(&vcpu->kvm->mmu_lock);
mmu_alloc_roots(vcpu);
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
kvm_mmu_flush_tlb(vcpu);
out:
@@ -1408,7 +1412,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
- mutex_lock(&vcpu->kvm->lock);
+ spin_lock(&vcpu->kvm->mmu_lock);
++vcpu->kvm->stat.mmu_pte_write;
kvm_mmu_audit(vcpu, "pre pte write");
if (gfn == vcpu->arch.last_pt_write_gfn
@@ -1477,7 +1481,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
}
}
kvm_mmu_audit(vcpu, "post pte write");
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
if (vcpu->arch.update_pte.page) {
kvm_release_page_clean(vcpu->arch.update_pte.page);
vcpu->arch.update_pte.page = NULL;
@@ -1493,15 +1497,15 @@ int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
up_read(¤t->mm->mmap_sem);
- mutex_lock(&vcpu->kvm->lock);
+ spin_lock(&vcpu->kvm->mmu_lock);
r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
return r;
}
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
{
- mutex_lock(&vcpu->kvm->lock);
+ spin_lock(&vcpu->kvm->mmu_lock);
while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
struct kvm_mmu_page *sp;
@@ -1510,7 +1514,7 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
kvm_mmu_zap_page(vcpu->kvm, sp);
++vcpu->kvm->stat.mmu_recycled;
}
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
}
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
@@ -1642,10 +1646,10 @@ void kvm_mmu_zap_all(struct kvm *kvm)
{
struct kvm_mmu_page *sp, *node;
- mutex_lock(&kvm->lock);
+ spin_lock(&kvm->mmu_lock);
list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
kvm_mmu_zap_page(kvm, sp);
- mutex_unlock(&kvm->lock);
+ spin_unlock(&kvm->mmu_lock);
kvm_flush_remote_tlbs(kvm);
}
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 3d7846b..a35b83a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -387,7 +387,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
*/
r = FNAME(walk_addr)(&walker, vcpu, addr, write_fault, user_fault,
fetch_fault);
- up_read(¤t->mm->mmap_sem);
/*
* The page is not mapped by the guest. Let the guest handle it.
@@ -396,12 +395,13 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
pgprintk("%s: guest page fault\n", __FUNCTION__);
inject_page_fault(vcpu, addr, walker.error_code);
vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
+ up_read(¤t->mm->mmap_sem);
return 0;
}
page = gfn_to_page(vcpu->kvm, walker.gfn);
- mutex_lock(&vcpu->kvm->lock);
+ spin_lock(&vcpu->kvm->mmu_lock);
shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
&write_pt, page);
pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__,
@@ -414,13 +414,15 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
* mmio: emulate if accessible, otherwise its a guest fault.
*/
if (shadow_pte && is_io_pte(*shadow_pte)) {
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ up_read(¤t->mm->mmap_sem);
return 1;
}
++vcpu->stat.pf_fixed;
kvm_mmu_audit(vcpu, "post page fault (fixed)");
- mutex_unlock(&vcpu->kvm->lock);
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ up_read(¤t->mm->mmap_sem);
return write_pt;
}
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 99fec63..4741806 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1476,7 +1476,6 @@ static int alloc_apic_access_page(struct kvm *kvm)
struct kvm_userspace_memory_region kvm_userspace_mem;
int r = 0;
- mutex_lock(&kvm->lock);
down_write(¤t->mm->mmap_sem);
if (kvm->arch.apic_access_page)
goto out;
@@ -1490,7 +1489,6 @@ static int alloc_apic_access_page(struct kvm *kvm)
kvm->arch.apic_access_page = gfn_to_page(kvm, 0xfee00);
out:
up_write(¤t->mm->mmap_sem);
- mutex_unlock(&kvm->lock);
return r;
}
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index a020fb2..2714068 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -104,7 +104,8 @@ struct kvm_memory_slot {
};
struct kvm {
- struct mutex lock; /* protects everything except vcpus */
+ struct mutex lock; /* protects the vcpus array and APIC accesses */
+ spinlock_t mmu_lock;
struct mm_struct *mm; /* userspace tied to this vm */
int nmemslots;
struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS +
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c462d7e..4295623 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -165,6 +165,7 @@ static struct kvm *kvm_create_vm(void)
kvm->mm = current->mm;
atomic_inc(&kvm->mm->mm_count);
+ spin_lock_init(&kvm->mmu_lock);
kvm_io_bus_init(&kvm->pio_bus);
mutex_init(&kvm->lock);
kvm_io_bus_init(&kvm->mmio_bus);
@@ -552,9 +553,7 @@ int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
addr = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(addr))
return -EFAULT;
- pagefault_disable();
r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
- pagefault_enable();
if (r)
return -EFAULT;
return 0;
--
1.5.3.7
--
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