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authorSean Christopherson <seanjc@google.com>2022-10-13 21:12:31 +0000
committerDavid Woodhouse <dwmw@amazon.co.uk>2022-11-30 19:25:24 +0000
commit58f5ee5fedd981e05cb086cba4e8f923c3727a04 (patch)
tree14e4ac0c59bb8d8bc5c16b6494779a4be983ab5a /virt
parent5762cb10235776dd1ed5f5f9d6c1aff2b73bec5c (diff)
downloadlwn-58f5ee5fedd981e05cb086cba4e8f923c3727a04.tar.gz
lwn-58f5ee5fedd981e05cb086cba4e8f923c3727a04.zip
KVM: Drop @gpa from exported gfn=>pfn cache check() and refresh() helpers
Drop the @gpa param from the exported check()+refresh() helpers and limit changing the cache's GPA to the activate path. All external users just feed in gpc->gpa, i.e. this is a fancy nop. Allowing users to change the GPA at check()+refresh() is dangerous as those helpers explicitly allow concurrent calls, e.g. KVM could get into a livelock scenario. It's also unclear as to what the expected behavior should be if multiple tasks attempt to refresh with different GPAs. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/pfncache.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index c1a772cedc4b..a805cc1544bf 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -76,18 +76,17 @@ void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm, unsigned long start,
}
}
-bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long len)
+bool kvm_gpc_check(struct gfn_to_pfn_cache *gpc, unsigned long len)
{
struct kvm_memslots *slots = kvm_memslots(gpc->kvm);
if (!gpc->active)
return false;
- if ((gpa & ~PAGE_MASK) + len > PAGE_SIZE)
+ if ((gpc->gpa & ~PAGE_MASK) + len > PAGE_SIZE)
return false;
- if (gpc->gpa != gpa || gpc->generation != slots->generation ||
- kvm_is_error_hva(gpc->uhva))
+ if (gpc->generation != slots->generation || kvm_is_error_hva(gpc->uhva))
return false;
if (!gpc->valid)
@@ -237,7 +236,8 @@ out_error:
return -EFAULT;
}
-int kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long len)
+static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa,
+ unsigned long len)
{
struct kvm_memslots *slots = kvm_memslots(gpc->kvm);
unsigned long page_offset = gpa & ~PAGE_MASK;
@@ -331,6 +331,11 @@ out_unlock:
return ret;
}
+
+int kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, unsigned long len)
+{
+ return __kvm_gpc_refresh(gpc, gpc->gpa, len);
+}
EXPORT_SYMBOL_GPL(kvm_gpc_refresh);
void kvm_gpc_init(struct gfn_to_pfn_cache *gpc, struct kvm *kvm,
@@ -371,7 +376,7 @@ int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long len)
gpc->active = true;
write_unlock_irq(&gpc->lock);
}
- return kvm_gpc_refresh(gpc, gpa, len);
+ return __kvm_gpc_refresh(gpc, gpa, len);
}
EXPORT_SYMBOL_GPL(kvm_gpc_activate);