On 04/12/2010 11:06 AM, Xiao Guangrong wrote:
- chain all unsync shadow pages then we can fetch them quickly
- flush local/remote tlb after all shadow page synced
Signed-off-by: Xiao Guangrong<xiaoguangrong@xxxxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/mmu.c | 82 ++++++++++++++++++---------------------
2 files changed, 39 insertions(+), 44 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index d463bc6..ae543fb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -207,6 +207,7 @@ struct kvm_mmu_page {
#define MMU_PAGE_UNSYNC 0x2
unsigned int flags;
unsigned int unsync_children;
+ struct list_head unsync_link;
union {
u64 *parent_pte; /* !multimapped */
struct hlist_head parent_ptes; /* multimapped, kvm_pte_chain */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 18eceb2..fcb6299 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -177,6 +177,8 @@ typedef int (*mmu_parent_walk_fn) (struct kvm_mmu_page *sp, u64 *spte);
static struct kmem_cache *pte_chain_cache;
static struct kmem_cache *rmap_desc_cache;
static struct kmem_cache *mmu_page_header_cache;
+static struct list_head unsync_mmu_page_list =
+ LIST_HEAD_INIT(unsync_mmu_page_list);
Does this really need to be global? Should be per guest.
static u64 __read_mostly shadow_trap_nonpresent_pte;
static u64 __read_mostly shadow_notrap_nonpresent_pte;
@@ -950,6 +952,7 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
sp->flags = 0;
sp->parent_pte = parent_pte;
+ INIT_LIST_HEAD(&sp->unsync_link);
--vcpu->kvm->arch.n_free_mmu_pages;
return sp;
}
@@ -1200,12 +1203,14 @@ static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
WARN_ON(!mmu_page_is_unsync(sp));
mmu_page_clear_unsync(sp);
+ list_del(&sp->unsync_link);
--kvm->stat.mmu_unsync;
}
Locking?
- if (protected)
- kvm_flush_remote_tlbs(vcpu->kvm);
+ if (list_empty(&unsync_mmu_page_list))
+ return;
Will this ever happen? In my experience we usually have a ton of
unsyncs lying around.
+ list_for_each_safe(p, next,&unsync_mmu_page_list) {
+ struct kvm_mmu_page *sp;
+ sp = list_entry(p, struct kvm_mmu_page, unsync_link);
+ __kvm_sync_page(vcpu, sp,&flush_local_tlb,&flush_remote_tlb);
}
That's counter to the point of unsync. We only want to sync the minimum
number of pages - all pages reachable by the new root. The others we
want to keep writeable to reduce our fault count.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
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