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From: Brijesh Singh <brijesh.singh@amd.com>
To: Laszlo Ersek <lersek@redhat.com>,
	edk2-devel-01 <edk2-devel@lists.01.org>
Cc: brijesh.singh@amd.com, Jordan Justen <jordan.l.justen@intel.com>
Subject: Re: [PATCH 2/2] OvmfPkg/PlatformDebugLibIoPort: write messages with IoWriteFifo8()
Date: Tue, 5 Sep 2017 09:33:15 -0500	[thread overview]
Message-ID: <9ab9bb4d-dfbf-8352-1506-77e191720524@amd.com> (raw)
In-Reply-To: <20170904155717.31591-3-lersek@redhat.com>



On 09/04/2017 10:57 AM, Laszlo Ersek wrote:
> Since commit 19c6d9feaaf8 ("MdePkg: Expand BaseIoLibIntrinsic (IoLib
> class) library", 2017-01-14), IoWriteFifo8() has been widely available to
> modules. Use it to print debug messages and assertion failures to the QEMU
> debug port, rather than open-coded loops.
> 
> In the general case this speeds up logging, because debug messages will
> now trap to QEMU once per message (as opposed to once per character), due
> to "REP OUTSB" in "MdePkg/Library/BaseIoLibIntrinsic/*/IoFifoSev.nasm".
> 
> In SEV guests, there is no speedup (SEV doesn't support the REP prefix).
> SEV is detected internally to BaseIoLibIntrinsic.
> 
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Acked-by: Brijesh Singh <brijesh.singh@amd.com>



  reply	other threads:[~2017-09-05 14:30 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-04 15:57 [PATCH 0/2] MdePkg, OvmfPkg: fix IoWriteFifo8(), and print debug messages with it Laszlo Ersek
2017-09-04 15:57 ` [PATCH 1/2] MdePkg/BaseIoLibIntrinsic: fix SEV (=unrolled) variants of IoWriteFifoXX() Laszlo Ersek
2017-09-05  1:40   ` Gao, Liming
2017-09-05 14:32   ` Brijesh Singh
2017-09-04 15:57 ` [PATCH 2/2] OvmfPkg/PlatformDebugLibIoPort: write messages with IoWriteFifo8() Laszlo Ersek
2017-09-05 14:33   ` Brijesh Singh [this message]
2017-09-11 20:30 ` [PATCH 0/2] MdePkg, OvmfPkg: fix IoWriteFifo8(), and print debug messages with it Laszlo Ersek

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