From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id A685221CFA5FC for ; Wed, 16 Aug 2017 09:45:16 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 39AC97EAB2; Wed, 16 Aug 2017 16:47:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 39AC97EAB2 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lersek@redhat.com Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-59.phx2.redhat.com [10.3.116.59]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9CBCD5D973; Wed, 16 Aug 2017 16:47:40 +0000 (UTC) To: Brijesh Singh , edk2-devel@lists.01.org Cc: Jordan Justen , Tom Lendacky , Ard Biesheuvel References: <1502710605-8058-1-git-send-email-brijesh.singh@amd.com> <1502710605-8058-11-git-send-email-brijesh.singh@amd.com> From: Laszlo Ersek Message-ID: Date: Wed, 16 Aug 2017 18:47:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1502710605-8058-11-git-send-email-brijesh.singh@amd.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 16 Aug 2017 16:47:42 +0000 (UTC) Subject: Re: [PATCH v2 10/23] OvmfPkg/VirtioLib: add VirtioMapAllBytesInSharedBuffer() helper function X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Aug 2017 16:45:16 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 08/14/17 13:36, Brijesh Singh wrote: > The function can be used for mapping the system physical address to virtio > device address using VIRTIO_DEVICE_PROTOCOL.MapSharedBuffer (). The > function helps centralizing error handling, and it allows caller to pass (1) some grammar bikeshedding: - s/helps centralizing/helps with centralizing/ - s/allows caller/allows the caller/ > in constant or other evaluated expression for NumberOfBytes. - s/expression/expressions/ > > Cc: Ard Biesheuvel > Cc: Jordan Justen > Cc: Tom Lendacky > Cc: Laszlo Ersek > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Brijesh Singh > --- > OvmfPkg/Include/Library/VirtioLib.h | 44 +++++++++++ > OvmfPkg/Library/VirtioLib/VirtioLib.c | 78 ++++++++++++++++++++ > 2 files changed, 122 insertions(+) > > diff --git a/OvmfPkg/Include/Library/VirtioLib.h b/OvmfPkg/Include/Library/VirtioLib.h > index 5badfb32917f..d8f24a5d68b1 100644 > --- a/OvmfPkg/Include/Library/VirtioLib.h > +++ b/OvmfPkg/Include/Library/VirtioLib.h > @@ -3,6 +3,7 @@ > Declarations of utility functions used by virtio device drivers. > > Copyright (C) 2012-2016, Red Hat, Inc. > + Copyright (C) 2017, AMD Inc, All rights reserved.
> > This program and the accompanying materials are licensed and made available > under the terms and conditions of the BSD License which accompanies this > @@ -235,4 +236,47 @@ Virtio10WriteFeatures ( > IN OUT UINT8 *DeviceStatus > ); > > +/** > + Provides the virtio device address required to access system memory from a > + DMA bus master. > + This part is slightly out of synch with the protocol definition itself (i.e., with VIRTIO_MAP_SHARED): the UEFI spec reference is missing. However, that's fine: this function diverges slightly from the spec -- that's exactly where the extra convenience comes from. So this is OK. > + @param[in] This The protocol instance pointer. > + (2) This should say instead: @param[in] VirtIo The virtio device for which the mapping is requested. > + @param[in] Operation Indicates if the bus master is going to > + read or write to system memory. > + > + @param[in] HostAddress The system memory address to map to shared > + buffer address. > + > + @param[in,out] NumberOfBytes On input the number of bytes to map. > + On output the number of bytes that were > + mapped. (3) This is wrong. In my v1 review , point (3), I wrote, Basically you can copy the MapSharedBuffer() documentation, just point out the extra logic for NumberOfBytes. That description is missing -- NumberOfBytes is an IN-only parameter here, and it is interpreted as a hard requirement. > + > + @param[out] DeviceAddress The resulting shared map address for the > + bus master to access the hosts HostAddress. > + > + @param[out] Mapping A resulting taken to pass to > + VIRTIO_UNMAP_SHARED. (4) s/taken/token/, as discussed before > + > + > + @retval EFI_SUCCESS The range was mapped for the returned > + NumberOfBytes. (5) This too should be adapted to our particular NumberOfBytes interpretation. > + @retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a > + common buffer. > + @retval EFI_INVALID_PARAMETER One or more parameters are invalid. > + @retval EFI_OUT_OF_RESOURCES The request could not be completed due to > + a lack of resources. (6) Please add, "This includes the case when NumberOfBytes bytes cannot be mapped in one consecutive range." > + @retval EFI_DEVICE_ERROR The system hardware could not map the > + requested address. > +**/ > +EFI_STATUS > +EFIAPI > +VirtioMapAllBytesInSharedBuffer ( > + IN VIRTIO_DEVICE_PROTOCOL *VirtIo, > + IN VIRTIO_MAP_OPERATION Operation, > + IN VOID *HostAddress, > + IN UINTN NumberOfBytes, > + OUT EFI_PHYSICAL_ADDRESS *DeviceAddress, > + OUT VOID **Mapping > + ); > #endif // _VIRTIO_LIB_H_ > diff --git a/OvmfPkg/Library/VirtioLib/VirtioLib.c b/OvmfPkg/Library/VirtioLib/VirtioLib.c > index 845f206369a3..ac0ae97f3692 100644 > --- a/OvmfPkg/Library/VirtioLib/VirtioLib.c > +++ b/OvmfPkg/Library/VirtioLib/VirtioLib.c > @@ -4,6 +4,7 @@ > > Copyright (C) 2012-2016, Red Hat, Inc. > Portion of Copyright (C) 2013, ARM Ltd. > + Copyright (C) 2017, AMD Inc, All rights reserved.
> > This program and the accompanying materials are licensed and made available > under the terms and conditions of the BSD License which accompanies this > @@ -414,3 +415,80 @@ Virtio10WriteFeatures ( > > return Status; > } > + > +/** > + Provides the virtio device address required to access system memory from a > + DMA bus master. > + > + @param[in] This The protocol instance pointer. > + > + @param[in] Operation Indicates if the bus master is going to > + read or write to system memory. > + > + @param[in] HostAddress The system memory address to map to shared > + buffer address. > + > + @param[in,out] NumberOfBytes On input the number of bytes to map. > + On output the number of bytes that were > + mapped. > + > + @param[out] DeviceAddress The resulting shared map address for the > + bus master to access the hosts HostAddress. > + > + @param[out] Mapping A resulting taken to pass to > + VIRTIO_UNMAP_SHARED. > + > + > + @retval EFI_SUCCESS The range was mapped for the returned > + NumberOfBytes. > + @retval EFI_UNSUPPORTED The HostAddress cannot be mapped as a > + common buffer. > + @retval EFI_INVALID_PARAMETER One or more parameters are invalid. > + @retval EFI_OUT_OF_RESOURCES The request could not be completed due to > + a lack of resources. > + @retval EFI_DEVICE_ERROR The system hardware could not map the > + requested address. > +**/ (7) Please sync this with points (2) through (6) above. > +EFI_STATUS > +EFIAPI > +VirtioMapAllBytesInSharedBuffer ( > + IN VIRTIO_DEVICE_PROTOCOL *VirtIo, > + IN VIRTIO_MAP_OPERATION Operation, > + IN VOID *HostAddress, > + IN UINTN NumberOfBytes, > + OUT EFI_PHYSICAL_ADDRESS *DeviceAddress, > + OUT VOID **Mapping > + ) > +{ > + EFI_STATUS Status; > + VOID *MapInfo; > + UINTN Size; > + EFI_PHYSICAL_ADDRESS PhysicalAddress; > + > + Size = NumberOfBytes; > + Status = VirtIo->MapSharedBuffer ( > + VirtIo, > + Operation, > + HostAddress, > + &Size, > + &PhysicalAddress, > + &MapInfo > + ); > + if (EFI_ERROR (Status)) { > + return Status; > + } > + > + if (Size < NumberOfBytes) { > + goto Failed; > + } > + > + *Mapping = MapInfo; > + *DeviceAddress = PhysicalAddress; > + > + return EFI_SUCCESS; > + > +Failed: > + VirtIo->UnmapSharedBuffer (VirtIo, MapInfo); > + *Mapping = NULL; > + return EFI_OUT_OF_RESOURCES; > +} > (8) The logic differs slightly from the previous version: in this version you set Mapping to NULL on error. I liked the previous version more; IMO we should not touch output parameters on error (that's why you introduced MapInfo earlier, to begin with). So I suggest dropping the NULL-ing on error. Thanks Laszlo