Luca Tettamanti wrote:
Hello,
my kernel just exploded :)
The host is running 2.6-git-current, with KVM modules from KVM-27
package. kernel is 32bit, SMP, with PREEMPT enabled, no HIGHMEM (but I'm
using CONFIG_VMSPLIT_3G_OPT=y). The CPU is a Core2 (hence I'm using
kvm-intel).
Guest was a Fedora7 setup DVD, which died somewhere during the
installation (anaconda was already active at that point). Bad news is
that I cannot reproduce the bug :|
Fortunately the trace clearly shows the problem (out of mmu working
memory on guest context switch). The attached patch should fix it. Let
me know if it works for you.
--
error compiling committee.c: too many arguments to function
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 0632d0b..0fdd5a6 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -543,6 +543,8 @@ 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);
+int kvm_mmu_load(struct kvm_vcpu *vcpu);
+void kvm_mmu_unload(struct kvm_vcpu *vcpu);
int kvm_hypercall(struct kvm_vcpu *vcpu, struct kvm_run *run);
@@ -554,6 +556,14 @@ static inline int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
return vcpu->mmu.page_fault(vcpu, gva, error_code);
}
+static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
+{
+ if (likely(vcpu->mmu.root_hpa != INVALID_PAGE))
+ return 0;
+
+ return kvm_mmu_load(vcpu);
+}
+
static inline int is_long_mode(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 283df03..5915d7a 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -949,9 +949,7 @@ static int nonpaging_init_context(struct kvm_vcpu *vcpu)
context->free = nonpaging_free;
context->root_level = 0;
context->shadow_root_level = PT32E_ROOT_LEVEL;
- mmu_alloc_roots(vcpu);
- ASSERT(VALID_PAGE(context->root_hpa));
- kvm_arch_ops->set_cr3(vcpu, context->root_hpa);
+ context->root_hpa = INVALID_PAGE;
return 0;
}
@@ -965,11 +963,6 @@ static void paging_new_cr3(struct kvm_vcpu *vcpu)
{
pgprintk("%s: cr3 %lx\n", __FUNCTION__, vcpu->cr3);
mmu_free_roots(vcpu);
- if (unlikely(vcpu->kvm->n_free_mmu_pages < KVM_MIN_FREE_MMU_PAGES))
- kvm_mmu_free_some_pages(vcpu);
- mmu_alloc_roots(vcpu);
- kvm_mmu_flush_tlb(vcpu);
- kvm_arch_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);
}
static void inject_page_fault(struct kvm_vcpu *vcpu,
@@ -1003,10 +996,7 @@ static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
context->free = paging_free;
context->root_level = level;
context->shadow_root_level = level;
- mmu_alloc_roots(vcpu);
- ASSERT(VALID_PAGE(context->root_hpa));
- kvm_arch_ops->set_cr3(vcpu, context->root_hpa |
- (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK)));
+ context->root_hpa = INVALID_PAGE;
return 0;
}
@@ -1025,10 +1015,7 @@ static int paging32_init_context(struct kvm_vcpu *vcpu)
context->free = paging_free;
context->root_level = PT32_ROOT_LEVEL;
context->shadow_root_level = PT32E_ROOT_LEVEL;
- mmu_alloc_roots(vcpu);
- ASSERT(VALID_PAGE(context->root_hpa));
- kvm_arch_ops->set_cr3(vcpu, context->root_hpa |
- (vcpu->cr3 & (CR3_PCD_MASK | CR3_WPT_MASK)));
+ context->root_hpa = INVALID_PAGE;
return 0;
}
@@ -1042,7 +1029,6 @@ static int init_kvm_mmu(struct kvm_vcpu *vcpu)
ASSERT(vcpu);
ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
- mmu_topup_memory_caches(vcpu);
if (!is_paging(vcpu))
return nonpaging_init_context(vcpu);
else if (is_long_mode(vcpu))
@@ -1064,16 +1050,31 @@ static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
{
+ destroy_kvm_mmu(vcpu);
+ return init_kvm_mmu(vcpu);
+}
+
+int kvm_mmu_load(struct kvm_vcpu *vcpu)
+{
int r;
- destroy_kvm_mmu(vcpu);
- r = init_kvm_mmu(vcpu);
- if (r < 0)
- goto out;
+ spin_lock(&vcpu->kvm->lock);
r = mmu_topup_memory_caches(vcpu);
+ if (r)
+ goto out;
+ mmu_alloc_roots(vcpu);
+ kvm_arch_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);
+ kvm_mmu_flush_tlb(vcpu);
out:
+ spin_unlock(&vcpu->kvm->lock);
return r;
}
+EXPORT_SYMBOL_GPL(kvm_mmu_load);
+
+void kvm_mmu_unload(struct kvm_vcpu *vcpu)
+{
+ mmu_free_roots(vcpu);
+}
static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
struct kvm_mmu_page *page,
diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index b621403..ed33f59 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1482,6 +1482,10 @@ static int svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
int r;
again:
+ r = kvm_mmu_reload(vcpu);
+ if (unlikely(r))
+ return r;
+
if (!vcpu->mmio_read_completed)
do_interrupt_requests(vcpu, kvm_run);
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 09e3609..a499989 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1987,6 +1987,10 @@ again:
vmx_save_host_state(vcpu);
kvm_load_guest_fpu(vcpu);
+ r = kvm_mmu_reload(vcpu);
+ if (unlikely(r))
+ goto out;
+
/*
* Loading guest fpu may have cleared host cr0.ts
*/
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