Subject: [PATCH 02/13] powerpc/64s: remove KVM SKIP test from instruction breakpoint handler

From: Nicholas Piggin <[email-masked]>
Date: Fri, 19 Feb 2021 16:35:31 +1000

The code being executed in KVM_GUEST_MODE_SKIP is hypervisor code with
MSR[IR]=0, so the faults of concern are the d-side ones caused by access
to guest context by the hypervisor.

Instruction breakpoint interrupts are not a concern here. It's unlikely
any good would come of causing breaks in this code, but skipping the
instruction that caused it won't help matters (e.g., skip the mtmsr that
sets MSR[DR]=0 or clears KVM_GUEST_MODE_SKIP).

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/exceptions-64s.S | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 5d0ad3b38e90..5bc689a546ae 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -2597,7 +2597,6 @@ EXC_VIRT_NONE(0x5200, 0x100)
 INT_DEFINE_BEGIN(instruction_breakpoint)
 	IVEC=0x1300
 #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
-	IKVM_SKIP=1
 	IKVM_REAL=1
 #endif
 INT_DEFINE_END(instruction_breakpoint)
-- 
2.23.0