lkml.org 
[lkml]   [2010]   [Jul]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH v5 4/9] KVM: MMU: introduce gfn_to_pfn_atomic() function
Introduce gfn_to_pfn_atomic(), it's the fast path and can used in atomic
context, the later patch will use it

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 32 +++++++++++++++++++++++++-------
2 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e796326..e0fb543 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -295,6 +295,7 @@ void kvm_release_page_dirty(struct page *page);
void kvm_set_page_dirty(struct page *page);
void kvm_set_page_accessed(struct page *page);

+pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn);
pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);
pfn_t gfn_to_pfn_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a60b6b0..5467fe5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -934,19 +934,25 @@ 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)
+static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr, bool atomic)
{
struct page *page[1];
int npages;
pfn_t pfn;

- might_sleep();
-
- npages = get_user_pages_fast(addr, 1, 1, page);
+ if (atomic)
+ npages = __get_user_pages_fast(addr, 1, 1, page);
+ else {
+ might_sleep();
+ npages = get_user_pages_fast(addr, 1, 1, page);
+ }

if (unlikely(npages != 1)) {
struct vm_area_struct *vma;

+ if (atomic)
+ goto return_bad_page;
+
down_read(&current->mm->mmap_sem);
if (is_hwpoison_address(addr)) {
up_read(&current->mm->mmap_sem);
@@ -959,6 +965,7 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr)
if (vma == NULL || addr < vma->vm_start ||
!(vma->vm_flags & VM_PFNMAP)) {
up_read(&current->mm->mmap_sem);
+return_bad_page:
get_page(bad_page);
return page_to_pfn(bad_page);
}
@@ -972,7 +979,7 @@ static pfn_t hva_to_pfn(struct kvm *kvm, unsigned long addr)
return pfn;
}

-pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
+pfn_t __gfn_to_pfn(struct kvm *kvm, gfn_t gfn, bool atomic)
{
unsigned long addr;

@@ -982,7 +989,18 @@ pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
return page_to_pfn(bad_page);
}

- return hva_to_pfn(kvm, addr);
+ return hva_to_pfn(kvm, addr, atomic);
+}
+
+pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn)
+{
+ return __gfn_to_pfn(kvm, gfn, true);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn_atomic);
+
+pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
+{
+ return __gfn_to_pfn(kvm, gfn, false);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn);

@@ -990,7 +1008,7 @@ 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);
+ return hva_to_pfn(kvm, addr, false);
}

struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
--
1.6.1.2



\
 
 \ /
  Last update: 2010-07-06 12:53    [from the cache]
©2003-2011 Jasper Spaans