The patch titled
KVM: MMU: Fix rare oops on guest context switch
has been added to the -mm tree. Its filename is
kvm-mmu-fix-rare-oops-on-guest-context-switch.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: KVM: MMU: Fix rare oops on guest context switch
From: Avi Kivity <avi@xxxxxxxxxxxx>
A guest context switch to an uncached cr3 can require allocation of
shadow pages, but we only recycle shadow pages in kvm_mmu_page_fault().
Move shadow page recycling to mmu_topup_memory_caches(), which is called
from both the page fault handler and from guest cr3 reload.
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/kvm/kvm.h | 10 +++++++---
drivers/kvm/mmu.c | 5 +++--
2 files changed, 10 insertions(+), 5 deletions(-)
diff -puN drivers/kvm/kvm.h~kvm-mmu-fix-rare-oops-on-guest-context-switch drivers/kvm/kvm.h
--- a/drivers/kvm/kvm.h~kvm-mmu-fix-rare-oops-on-guest-context-switch
+++ a/drivers/kvm/kvm.h
@@ -619,7 +619,7 @@ unsigned long segment_base(u16 selector)
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *old, const u8 *new, int bytes);
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva);
-void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
+void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
int kvm_mmu_load(struct kvm_vcpu *vcpu);
void kvm_mmu_unload(struct kvm_vcpu *vcpu);
@@ -628,11 +628,15 @@ int kvm_hypercall(struct kvm_vcpu *vcpu,
static inline int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
u32 error_code)
{
- if (unlikely(vcpu->kvm->n_free_mmu_pages < KVM_MIN_FREE_MMU_PAGES))
- kvm_mmu_free_some_pages(vcpu);
return vcpu->mmu.page_fault(vcpu, gva, error_code);
}
+static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
+{
+ if (unlikely(vcpu->kvm->n_free_mmu_pages < KVM_MIN_FREE_MMU_PAGES))
+ __kvm_mmu_free_some_pages(vcpu);
+}
+
static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
{
if (likely(vcpu->mmu.root_hpa != INVALID_PAGE))
diff -puN drivers/kvm/mmu.c~kvm-mmu-fix-rare-oops-on-guest-context-switch drivers/kvm/mmu.c
--- a/drivers/kvm/mmu.c~kvm-mmu-fix-rare-oops-on-guest-context-switch
+++ a/drivers/kvm/mmu.c
@@ -273,12 +273,14 @@ static int mmu_topup_memory_caches(struc
int r;
r = __mmu_topup_memory_caches(vcpu, GFP_NOWAIT);
+ kvm_mmu_free_some_pages(vcpu);
if (r < 0) {
spin_unlock(&vcpu->kvm->lock);
kvm_arch_ops->vcpu_put(vcpu);
r = __mmu_topup_memory_caches(vcpu, GFP_KERNEL);
kvm_arch_ops->vcpu_load(vcpu);
spin_lock(&vcpu->kvm->lock);
+ kvm_mmu_free_some_pages(vcpu);
}
return r;
}
@@ -1208,7 +1210,7 @@ int kvm_mmu_unprotect_page_virt(struct k
return kvm_mmu_unprotect_page(vcpu, gpa >> PAGE_SHIFT);
}
-void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
+void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
{
while (vcpu->kvm->n_free_mmu_pages < KVM_REFILL_PAGES) {
struct kvm_mmu_page *page;
@@ -1218,7 +1220,6 @@ void kvm_mmu_free_some_pages(struct kvm_
kvm_mmu_zap_page(vcpu->kvm, page);
}
}
-EXPORT_SYMBOL_GPL(kvm_mmu_free_some_pages);
static void free_mmu_pages(struct kvm_vcpu *vcpu)
{
_
Patches currently in -mm which might be from avi@xxxxxxxxxxxx are
kvm-mmu-fix-rare-oops-on-guest-context-switch.patch
git-kvm.patch
time-simplify-smp_call_function_single-call-sequence.patch
move-preempt_notifiers-into-an-always-included-kconfig.patch
-
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