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From: Fabiano Rosas <farosas@linux.ibm.com>
To: Nicholas Piggin <npiggin@gmail.com>, kvm-ppc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org, Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH 02/13] powerpc/64s: remove KVM SKIP test from instruction breakpoint handler
Date: Mon, 22 Feb 2021 19:22:51 -0300	[thread overview]
Message-ID: <87k0qzyc78.fsf@linux.ibm.com> (raw)
In-Reply-To: <20210219063542.1425130-3-npiggin@gmail.com>

Nicholas Piggin <npiggin@gmail.com> writes:

> 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 <npiggin@gmail.com>

Reviewed-by: Fabiano Rosas <farosas@linux.ibm.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 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)

  reply	other threads:[~2021-02-22 22:23 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-19  6:35 [PATCH 00/13] KVM: PPC: Book3S: C-ify the P9 entry/exit code Nicholas Piggin
2021-02-19  6:35 ` [PATCH 01/13] powerpc/64s: Remove KVM handler support from CBE_RAS interrupts Nicholas Piggin
2021-02-22 22:22   ` Fabiano Rosas
2021-02-19  6:35 ` [PATCH 02/13] powerpc/64s: remove KVM SKIP test from instruction breakpoint handler Nicholas Piggin
2021-02-22 22:22   ` Fabiano Rosas [this message]
2021-02-19  6:35 ` [PATCH 03/13] KVM: PPC: Book3S HV: Ensure MSR[ME] is always set in guest MSR Nicholas Piggin
2021-02-22 22:23   ` Fabiano Rosas
2021-02-19  6:35 ` [PATCH 04/13] KVM: PPC: Book3S 64: remove unused kvmppc_h_protect argument Nicholas Piggin
2021-02-19  6:35 ` [PATCH 05/13] KVM: PPC: Book3S 64: move KVM interrupt entry to a common entry point Nicholas Piggin
2021-02-19  6:35 ` [PATCH 06/13] KVM: PPC: Book3S 64: Move GUEST_MODE_SKIP test into KVM Nicholas Piggin
2021-02-22 22:40   ` Fabiano Rosas
2021-02-19  6:35 ` [PATCH 07/13] KVM: PPC: Book3S 64: add hcall interrupt handler Nicholas Piggin
2021-02-19  6:35 ` [PATCH 08/13] KVM: PPC: Book3S HV: Move hcall early register setup to KVM Nicholas Piggin
2021-02-19  6:35 ` [PATCH 09/13] KVM: PPC: Book3S HV: Move interrupt " Nicholas Piggin
2021-02-19  6:35 ` [PATCH 10/13] KVM: PPC: Book3S HV: move bad_host_intr check to HV handler Nicholas Piggin
2021-02-19  6:35 ` [PATCH 11/13] KVM: PPC: Book3S HV: Minimise hcall handler calling convention differences Nicholas Piggin
2021-02-19  6:35 ` [PATCH 12/13] KVM: PPC: Book3S HV: Move radix MMU switching together in the P9 path Nicholas Piggin
2021-02-24 20:36   ` Fabiano Rosas
2021-02-25 10:59     ` Nicholas Piggin
2021-02-19  6:35 ` [PATCH 13/13] KVM: PPC: Book3S HV: Implement the rest of the P9 entry/exit handling in C Nicholas Piggin

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