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authorGleb Natapov <gleb@redhat.com>2010-10-14 11:22:46 +0200
committerAvi Kivity <avi@redhat.com>2011-01-12 11:21:39 +0200
commitaf585b921e5d1e919947c4b1164b59507fe7cd7b (patch)
treed0d4cc753d4d58934c5986733d7340fe69e523de /virt/kvm/kvm_main.c
parent010c520e20413dfd567d568aba2b7238acd37e33 (diff)
downloadlinaro-lsk-af585b921e5d1e919947c4b1164b59507fe7cd7b.tar.gz
KVM: Halt vcpu if page it tries to access is swapped out
If a guest accesses swapped out memory do not swap it in from vcpu thread context. Schedule work to do swapping and put vcpu into halted state instead. Interrupts will still be delivered to the guest and if interrupt will cause reschedule guest will continue to run another task. [avi: remove call to get_user_pages_noio(), nacked by Linus; this makes everything synchrnous again] Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'virt/kvm/kvm_main.c')
-rw-r--r--virt/kvm/kvm_main.c48
1 files changed, 37 insertions, 11 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5225052aebc..75fd590c021 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -55,6 +55,7 @@
#include <asm-generic/bitops/le.h>
#include "coalesced_mmio.h"
+#include "async_pf.h"
#define CREATE_TRACE_POINTS
#include <trace/events/kvm.h>
@@ -186,6 +187,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
init_waitqueue_head(&vcpu->wq);
+ kvm_async_pf_vcpu_init(vcpu);
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page) {
@@ -946,15 +948,20 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
-static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic)
+static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic,
+ bool *async)
{
struct page *page[1];
- int npages;
+ int npages = 0;
pfn_t pfn;
- if (atomic)
+ /* we can do it either atomically or asynchronously, not both */
+ BUG_ON(atomic && async);
+
+ if (atomic || async)
npages = __get_user_pages_fast(addr, 1, 1, page);
- else {
+
+ if (unlikely(npages != 1) && !atomic) {
might_sleep();
npages = get_user_pages_fast(addr, 1, 1, page);
}
@@ -976,6 +983,9 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic)
if (vma == NULL || addr < vma->vm_start ||
!(vma->vm_flags & VM_PFNMAP)) {
+ if (async && !(vma->vm_flags & VM_PFNMAP) &&
+ (vma->vm_flags & VM_WRITE))
+ *async = true;
up_read(&current->mm->mmap_sem);
return_fault_page:
get_page(fault_page);
@@ -993,32 +1003,41 @@ return_fault_page:
pfn_t hva_to_pfn_atomic(struct kvm *kvm, unsigned long addr)
{
- return hva_to_pfn(kvm, addr, true);
+ return hva_to_pfn(kvm, addr, true, NULL);
}
EXPORT_SYMBOL_GPL(hva_to_pfn_atomic);
-static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic)
+static pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic, bool *async)
{
unsigned long addr;
+ if (async)
+ *async = false;
+
addr = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(addr)) {
get_page(bad_page);
return page_to_pfn(bad_page);
}
- return hva_to_pfn(kvm, addr, atomic);
+ return hva_to_pfn(kvm, addr, atomic, async);
}
pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn)
{
- return __gfn_to_pfn(kvm, gfn, true);
+ return __gfn_to_pfn(kvm, gfn, true, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_atomic);
+pfn_t gfn_to_pfn_async(struct kvm *kvm, gfn_t gfn, bool *async)
+{
+ return __gfn_to_pfn(kvm, gfn, false, async);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn_async);
+
pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
{
- return __gfn_to_pfn(kvm, gfn, false);
+ return __gfn_to_pfn(kvm, gfn, false, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn);
@@ -1026,7 +1045,7 @@ pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn)
{
unsigned long addr = gfn_to_hva_memslot(slot, gfn);
- return hva_to_pfn(kvm, addr, false);
+ return hva_to_pfn(kvm, addr, false, NULL);
}
int gfn_to_page_many_atomic(struct kvm *kvm, gfn_t gfn, struct page **pages,
@@ -2336,6 +2355,10 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
goto out_free_5;
}
+ r = kvm_async_pf_init();
+ if (r)
+ goto out_free;
+
kvm_chardev_ops.owner = module;
kvm_vm_fops.owner = module;
kvm_vcpu_fops.owner = module;
@@ -2343,7 +2366,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
r = misc_register(&kvm_dev);
if (r) {
printk(KERN_ERR "kvm: misc device register failed\n");
- goto out_free;
+ goto out_unreg;
}
kvm_preempt_ops.sched_in = kvm_sched_in;
@@ -2353,6 +2376,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
return 0;
+out_unreg:
+ kvm_async_pf_deinit();
out_free:
kmem_cache_destroy(kvm_vcpu_cache);
out_free_5:
@@ -2385,6 +2410,7 @@ void kvm_exit(void)
kvm_exit_debug();
misc_deregister(&kvm_dev);
kmem_cache_destroy(kvm_vcpu_cache);
+ kvm_async_pf_deinit();
sysdev_unregister(&kvm_sysdev);
sysdev_class_unregister(&kvm_sysdev_class);
unregister_reboot_notifier(&kvm_reboot_notifier);