[PATCH v4 09/46] powerpc/64s: remove KVM SKIP test from instruction breakpoint handler

Nicholas Piggin npiggin at gmail.com
Tue Mar 23 12:02:28 AEDT 2021


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).

Reviewed-by: Daniel Axtens <dja at axtens.net>
Reviewed-by: Fabiano Rosas <farosas at linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 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 a0515cb829c2..c9c446ccff54 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -2553,7 +2553,6 @@ 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



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