From: "Laszlo Ersek" <lersek@redhat.com>
To: Damian Nikodem <damian.nikodem@intel.com>, devel@edk2.groups.io
Cc: Eric Dong <eric.dong@intel.com>, Ray Ni <ray.ni@intel.com>,
Benjamin You <benjamin.you@intel.com>,
Krzysztof Rusocki <krzysztof.rusocki@intel.com>
Subject: Re: [PATCH v3] UefiCpuPkg: Fix potential spinLock issue in SmmStartupThisAp
Date: Wed, 11 Sep 2019 16:45:53 +0200 [thread overview]
Message-ID: <0cdd6b09-8d44-9aa3-df53-89c69aa7cf80@redhat.com> (raw)
In-Reply-To: <20190911082301.1488-1-damian.nikodem@intel.com>
On 09/11/19 10:23, Damian Nikodem wrote:
> Due to needs a tackling the deficiency of the AP API, is necessary to ensure that in non-blocking mode
> previous AP executed command is finished before start new one.
>
> To remedy above:
> 1) execute AcquireSpinLock instead AcquireSpinLockOrFail - this will ensure time "window" to eliminate potential
> race condition beetwen BSP and AP spinLock release in non-blocking mode.
> This also will eliminate possibility to start executing new AP function before last is finished.
> 2) remove returns EFI_STATUS - EFI_NOT_READY - in new scenario returned status is not necessary to caller.
>
> Signed-off-by: Damian Nikodem <damian.nikodem@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Benjamin You <benjamin.you@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Krzysztof Rusocki <krzysztof.rusocki@intel.com>
Eric, Ray, please don't wait for my feedback on this one. It would be
prudent for me to test this, but I got no time.
Thanks
Laszlo
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> index d8d2b6f444..0685637c2b 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> @@ -1235,14 +1235,9 @@ InternalSmmStartupThisAp (
> return EFI_INVALID_PARAMETER;
> }
>
> - if (Token == NULL) {
> - AcquireSpinLock (mSmmMpSyncData->CpuData[CpuIndex].Busy);
> - } else {
> - if (!AcquireSpinLockOrFail (mSmmMpSyncData->CpuData[CpuIndex].Busy)) {
> - DEBUG((DEBUG_ERROR, "Can't acquire mSmmMpSyncData->CpuData[%d].Busy\n", CpuIndex));
> - return EFI_NOT_READY;
> - }
> + AcquireSpinLock (mSmmMpSyncData->CpuData[CpuIndex].Busy);
>
> + if (Token != NULL) {
> *Token = (MM_COMPLETION) CreateToken ();
> }
> --------------------------------------------------------------------
>
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next prev parent reply other threads:[~2019-09-11 14:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 8:23 [PATCH v3] UefiCpuPkg: Fix potential spinLock issue in SmmStartupThisAp Damian Nikodem
2019-09-11 14:45 ` Laszlo Ersek [this message]
2019-09-11 17:37 ` Ni, Ray
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