From: James Morse james.morse@arm.com
commit 1229630af88620f6e3a621a1ebd1ca14d9340df7 upstream.
Prior to commit defe21f49bc9 ("KVM: arm64: Move PC rollback on SError to HYP"), when an SError is synchronised due to another exception, KVM handles the SError first. If the guest survives, the instruction that triggered the original exception is re-exectued to handle the first exception. HVC is treated as a special case as the instruction wouldn't normally be re-exectued, as its not a trap.
Commit defe21f49bc9 didn't preserve the behaviour of the 'return 1' that skips the rest of handle_exit().
Since commit defe21f49bc9, KVM will try to handle the SError and the original exception at the same time. When the exception was an HVC, fixup_guest_exit() has already rolled back ELR_EL2, meaning if the guest has virtual SError masked, it will execute and handle the HVC twice.
Restore the original behaviour.
Fixes: defe21f49bc9 ("KVM: arm64: Move PC rollback on SError to HYP") Cc: stable@vger.kernel.org Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20220127122052.1584324-4-james.morse@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kvm/handle_exit.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -226,6 +226,14 @@ int handle_exit(struct kvm_vcpu *vcpu, i { struct kvm_run *run = vcpu->run;
+ if (ARM_SERROR_PENDING(exception_index)) { + /* + * The SError is handled by handle_exit_early(). If the guest + * survives it will re-execute the original instruction. + */ + return 1; + } + exception_index = ARM_EXCEPTION_CODE(exception_index);
switch (exception_index) {