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From: "Nicholas Piggin" <npiggin@gmail.com>
To: "Rohan McLure" <rmclure@linux.ibm.com>, <linuxppc-dev@lists.ozlabs.org>
Cc: arnd@arndb.de
Subject: Re: [PATCH 09/12] powerpc: Mark writes registering ipi to host cpu through kvm
Date: Tue, 09 May 2023 12:30:08 +1000	[thread overview]
Message-ID: <CSHE6J2OCIAI.2G4GIJFTX3JDR@wheely> (raw)
In-Reply-To: <20230508020120.218494-10-rmclure@linux.ibm.com>

On Mon May 8, 2023 at 12:01 PM AEST, Rohan McLure wrote:
> Mark writes to hypervisor ipi state so that KCSAN recognises these
> asynchronous issue of kvmppc_{set,clear}_host_ipi to be intended, with
> atomic writes.

How about READ_ONCE for the read side of host_ipi?

Thanks,
Nick

>
> Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/kvm_ppc.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
> index bc57d058ad5b..d701df006c08 100644
> --- a/arch/powerpc/include/asm/kvm_ppc.h
> +++ b/arch/powerpc/include/asm/kvm_ppc.h
> @@ -548,12 +548,12 @@ static inline void kvmppc_set_host_ipi(int cpu)
>  	 * pairs with the barrier in kvmppc_clear_host_ipi()
>  	 */
>  	smp_mb();
> -	paca_ptrs[cpu]->kvm_hstate.host_ipi = 1;
> +	WRITE_ONCE(paca_ptrs[cpu]->kvm_hstate.host_ipi, 1);
>  }
>  
>  static inline void kvmppc_clear_host_ipi(int cpu)
>  {
> -	paca_ptrs[cpu]->kvm_hstate.host_ipi = 0;
> +	WRITE_ONCE(paca_ptrs[cpu]->kvm_hstate.host_ipi, 0);
>  	/*
>  	 * order clearing of host_ipi flag vs. processing of IPI messages
>  	 *
> -- 
> 2.37.2


  reply	other threads:[~2023-05-09  2:31 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-08  2:01 [PATCH 00/12] powerpc: KCSAN fix warnings and mark accesses Rohan McLure
2023-05-08  2:01 ` [PATCH 01/12] powerpc: qspinlock: Fix qnode->locked value interpretation Rohan McLure
2023-05-09  2:01   ` Nicholas Piggin
2023-05-09  4:26     ` Rohan McLure
2023-05-08  2:01 ` [PATCH 02/12] powerpc: qspinlock: Mark accesses to qnode lock checks Rohan McLure
2023-05-09  2:02   ` Nicholas Piggin
2023-05-08  2:01 ` [PATCH 03/12] powerpc: qspinlock: Enforce qnode writes prior to publishing to queue Rohan McLure
2023-05-09  2:04   ` Nicholas Piggin
2023-05-09  5:26     ` Rohan McLure
2023-05-09  6:45       ` Nicholas Piggin
2023-05-08  2:01 ` [PATCH 04/12] asm-generic/mmiowb: Mark accesses to fix KCSAN warnings Rohan McLure
2023-05-08  6:30   ` Arnd Bergmann
2023-05-08 15:44   ` [PATCH 4/12] " Gautam Menghani
2023-05-09  2:16   ` [PATCH 04/12] " Nicholas Piggin
2023-05-08  2:01 ` [PATCH 05/12] powerpc: Mark [h]ssr_valid accesses in check_return_regs_valid Rohan McLure
2023-05-09  2:17   ` Nicholas Piggin
2023-05-08  2:01 ` [PATCH 06/12] powerpc: Mark accesses to power_save callback in arch_cpu_idle Rohan McLure
2023-05-09  2:21   ` Nicholas Piggin
2023-05-08  2:01 ` [PATCH 07/12] powerpc: powernv: Fix KCSAN datarace warnings on idle_state contention Rohan McLure
2023-05-09  2:26   ` Nicholas Piggin
2023-05-10  2:00     ` Rohan McLure
2023-05-08  2:01 ` [PATCH 08/12] powerpc: Annotate accesses to ipi message flags Rohan McLure
2023-05-09  2:28   ` Nicholas Piggin
2023-05-08  2:01 ` [PATCH 09/12] powerpc: Mark writes registering ipi to host cpu through kvm Rohan McLure
2023-05-09  2:30   ` Nicholas Piggin [this message]
2023-05-08  2:01 ` [PATCH 10/12] powerpc: powernv: Annotate data races in opal events Rohan McLure
2023-05-09  2:31   ` Nicholas Piggin
2023-05-08  2:01 ` [PATCH 11/12] powerpc: powernv: Annotate asynchronous access to opal tokens Rohan McLure
2023-05-08  2:01 ` [PATCH 12/12] powerpc: Mark asynchronous accesses to irq_data Rohan McLure

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