On 11/01/2023 18:06, David Woodhouse wrote:
From: David Woodhouse <dwmw@xxxxxxxxxxxx>
In commit 5ec3289b31 ("KVM: x86/xen: Compatibility fixes for shared runstate
area") we declared it safe to obtain two gfn_to_pfn_cache locks at the same
time:
/*
* The guest's runstate_info is split across two pages and we
* need to hold and validate both GPCs simultaneously. We can
* declare a lock ordering GPC1 > GPC2 because nothing else
* takes them more than one at a time.
*/
However, we forgot to tell lockdep. Do so, by setting a subclass on the
first lock before taking the second.
Fixes: 5ec3289b31 ("KVM: x86/xen: Compatibility fixes for shared runstate area")
Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
arch/x86/kvm/xen.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
Reviewed-by: Paul Durrant <paul@xxxxxxx>
