From: Gleb Natapov <gleb@xxxxxxxxxx>
Introduce kvm_read_guest_cached() function in addition to write one we
already have.
[ by glauber: export function signature in kvm header ]
Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
Signed-off-by: Glauber Costa <glommer@xxxxxxxxxx>
---
include/linux/kvm_host.h | 2 ++
virt/kvm/kvm_main.c | 20 ++++++++++++++++++++
2 files changed, 22 insertions(+), 0 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 31ebb59..f7df0a3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -381,6 +381,8 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
unsigned long len);
int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len);
+int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
+ void *data, unsigned long len);
int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn, const void *data,
int offset, int len);
int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 11d2783..d5ef9eb 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1418,6 +1418,26 @@ int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
}
EXPORT_SYMBOL_GPL(kvm_write_guest_cached);
+int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
+ void *data, unsigned long len)
+{
+ struct kvm_memslots *slots = kvm_memslots(kvm);
+ int r;
+
+ if (slots->generation != ghc->generation)
+ kvm_gfn_to_hva_cache_init(kvm, ghc, ghc->gpa);
+
+ if (kvm_is_error_hva(ghc->hva))
+ return -EFAULT;
+
+ r = __copy_from_user(data, (void __user *)ghc->hva, len);
+ if (r)
+ return -EFAULT;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_read_guest_cached);
+
int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len)
{
return kvm_write_guest_page(kvm, gfn, (const void *) empty_zero_page,
--
1.7.3.4
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