diff mbox series

[v13,14/85] KVM: Return ERR_SIGPENDING from hva_to_pfn() if GUP returns -EGAIN

Message ID 20241010182427.1434605-15-seanjc@google.com
State Accepted
Headers show
Series KVM: Stop grabbing references to PFNMAP'd pages | expand

Commit Message

Sean Christopherson Oct. 10, 2024, 6:23 p.m. UTC 
Treat an -EAGAIN return from GUP the same as -EINTR and immediately report
to the caller that a signal is pending.  GUP only returns -EAGAIN if
the _initial_ mmap_read_lock_killable() fails, which in turn onnly fails
if a signal is pending

Note, rwsem_down_read_slowpath() actually returns -EINTR, so GUP is really
just making life harder than it needs to be.  And the call to
mmap_read_lock_killable() in the retry path returns its -errno verbatim,
i.e. GUP (and thus KVM) is already handling locking failure this way, but
only some of the time.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 virt/kvm/kvm_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 17acc75990a5..ebba5d22db2d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2946,7 +2946,7 @@  kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool *async,
 				 writable, &pfn);
 	if (npages == 1)
 		return pfn;
-	if (npages == -EINTR)
+	if (npages == -EINTR || npages == -EAGAIN)
 		return KVM_PFN_ERR_SIGPENDING;
 
 	mmap_read_lock(current->mm);