diff options
| author | Sean Christopherson <seanjc@google.com> | 2024-03-19 17:15:42 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-04-08 13:20:24 -0700 |
| commit | fc62a4e8dee2d1a9037e8cdeaa52ba67457f7300 (patch) | |
| tree | 765d6ba61f0775c3953518d4bd1257a6182a2912 /virt/kvm | |
| parent | 5c9ca4ed890889a2b7c300c4f63f3baf3f63383f (diff) | |
KVM: Explicitly disallow activatating a gfn_to_pfn_cache with INVALID_GPA
Explicit disallow activating a gfn_to_pfn_cache with an error gpa, i.e.
INVALID_GPA, to ensure that KVM doesn't mistake a GPA-based cache for an
HVA-based cache (KVM uses INVALID_GPA as a magic value to differentiate
between GPA-based and HVA-based caches).
WARN if KVM attempts to activate a cache with INVALID_GPA, purely so that
new caches need to at least consider what to do with a "bad" GPA, as all
existing usage of kvm_gpc_activate() guarantees gpa != INVALID_GPA. I.e.
removing the WARN in the future is completely reasonable if doing so would
yield cleaner/better code overall.
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/20240320001542.3203871-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'virt/kvm')
| -rw-r--r-- | virt/kvm/pfncache.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 91b0e329006b..f618719644e0 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -418,6 +418,13 @@ static int __kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned long len) { + /* + * Explicitly disallow INVALID_GPA so that the magic value can be used + * by KVM to differentiate between GPA-based and HVA-based caches. + */ + if (WARN_ON_ONCE(kvm_is_error_gpa(gpa))) + return -EINVAL; + return __kvm_gpc_activate(gpc, gpa, KVM_HVA_ERR_BAD, len); } |