KVM: arm64: pvtime: Fix stolen time accounting across migration
When updating the stolen time we should always read the current
stolen time from the user provided memory, not from a kernel
cache. If we use a cache then we'll end up resetting stolen time
to zero on the first update after migration.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200804170604.42662-5-drjones@redhat.com
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 84371fb..05e3c2f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -749,6 +749,26 @@ int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
gpa_t gpa, unsigned long len);
+#define __kvm_get_guest(kvm, gfn, offset, v) \
+({ \
+ unsigned long __addr = gfn_to_hva(kvm, gfn); \
+ typeof(v) __user *__uaddr = (typeof(__uaddr))(__addr + offset); \
+ int __ret = -EFAULT; \
+ \
+ if (!kvm_is_error_hva(__addr)) \
+ __ret = get_user(v, __uaddr); \
+ __ret; \
+})
+
+#define kvm_get_guest(kvm, gpa, v) \
+({ \
+ gpa_t __gpa = gpa; \
+ struct kvm *__kvm = kvm; \
+ \
+ __kvm_get_guest(__kvm, __gpa >> PAGE_SHIFT, \
+ offset_in_page(__gpa), v); \
+})
+
#define __kvm_put_guest(kvm, gfn, offset, v) \
({ \
unsigned long __addr = gfn_to_hva(kvm, gfn); \