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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v1 17/21] Ovmf/Xen: add Xen PV console SerialPortLib driver
On 23 January 2015 at 18:54, Stefano Stabellini
<stefano.stabellini@xxxxxxxxxxxxx> wrote:
> On Fri, 23 Jan 2015, Ard Biesheuvel wrote:
>> This implements a SerialPortLib instance that wires up to the
>> PV console ring used by domU guests. Also imports the required
>> upstream Xen io/console.h header.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.0
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> ---
>> OvmfPkg/Include/IndustryStandard/Xen/io/console.h | 51 +++++++
>> .../XenConsoleSerialPortLib.c | 147
>> +++++++++++++++++++++
>> .../XenConsoleSerialPortLib.inf | 34 +++++
>> 3 files changed, 232 insertions(+)
>> create mode 100644 OvmfPkg/Include/IndustryStandard/Xen/io/console.h
>> create mode 100644
>> OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
>> create mode 100644
>> OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.inf
>>
>> diff --git a/OvmfPkg/Include/IndustryStandard/Xen/io/console.h
>> b/OvmfPkg/Include/IndustryStandard/Xen/io/console.h
>> new file mode 100644
>> index 000000000000..f1caa9765bcf
>> --- /dev/null
>> +++ b/OvmfPkg/Include/IndustryStandard/Xen/io/console.h
>> @@ -0,0 +1,51 @@
>> +/******************************************************************************
>> + * console.h
>> + *
>> + * Console I/O interface for Xen guest OSes.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> copy
>> + * of this software and associated documentation files (the "Software"), to
>> + * deal in the Software without restriction, including without limitation
>> the
>> + * rights to use, copy, modify, merge, publish, distribute, sublicense,
>> and/or
>> + * sell copies of the Software, and to permit persons to whom the Software
>> is
>> + * furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included
>> in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
>> OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>> THE
>> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
>> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
>> + * DEALINGS IN THE SOFTWARE.
>> + *
>> + * Copyright (c) 2005, Keir Fraser
>> + */
>> +
>> +#ifndef __XEN_PUBLIC_IO_CONSOLE_H__
>> +#define __XEN_PUBLIC_IO_CONSOLE_H__
>> +
>> +typedef UINT32 XENCONS_RING_IDX;
>> +
>> +#define MASK_XENCONS_IDX(idx, ring) ((idx) & (sizeof(ring)-1))
>> +
>> +struct xencons_interface {
>> + char in[1024];
>> + char out[2048];
>> + XENCONS_RING_IDX in_cons, in_prod;
>> + XENCONS_RING_IDX out_cons, out_prod;
>> +};
>> +
>> +#endif /* __XEN_PUBLIC_IO_CONSOLE_H__ */
>> +
>> +/*
>> + * Local variables:
>> + * mode: C
>> + * c-file-style: "BSD"
>> + * c-basic-offset: 4
>> + * tab-width: 4
>> + * indent-tabs-mode: nil
>> + * End:
>> + */
>> diff --git
>> a/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
>> b/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
>> new file mode 100644
>> index 000000000000..97344dc4efb0
>> --- /dev/null
>> +++ b/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.c
>> @@ -0,0 +1,147 @@
>> +/** @file
>> + Xen console SerialPortLib instance
>> +
>> + Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR>
>> +
>> + This program and the accompanying materials
>> + are licensed and made available under the terms and conditions of the BSD
>> License
>> + which accompanies this distribution. The full text of the license may be
>> found at
>> + http://opensource.org/licenses/bsd-license.php
>> +
>> + THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
>> + WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR
>> IMPLIED.
>> +
>> +**/
>> +
>> +#include <Base.h>
>> +#include <Uefi/UefiBaseType.h>
>> +
>> +#include <Library/BaseLib.h>
>> +#include <Library/SerialPortLib.h>
>> +#include <Library/XenHypercallLib.h>
>> +
>> +#include <IndustryStandard/Xen/io/console.h>
>> +#include <IndustryStandard/Xen/hvm/params.h>
>> +#include <IndustryStandard/Xen/event_channel.h>
>> +
>> +STATIC evtchn_send_t mXenConsoleEventChain;
>> +STATIC struct xencons_interface *mXenConsoleInterface;
>> +
>> +RETURN_STATUS
>> +EFIAPI
>> +SerialPortInitialize (
>> + VOID
>> + )
>> +{
>> + mXenConsoleEventChain.port = (UINT32)XenHypercallHvmGetParam
>> (HVM_PARAM_CONSOLE_EVTCHN);
>> + mXenConsoleInterface = (struct xencons_interface *)(UINTN)
>> + (XenHypercallHvmGetParam (HVM_PARAM_CONSOLE_PFN) << EFI_PAGE_SHIFT);
>> +
>> + //
>> + // No point in ASSERT'ing here as we won't be seeing the output
>> + //
>> + return RETURN_SUCCESS;
>> +}
>> +
>> +/**
>> + Write data to serial device.
>> +
>> + @param Buffer Point of data buffer which need to be written.
>> + @param NumberOfBytes Number of output bytes which are cached in
>> Buffer.
>> +
>> + @retval 0 Write data failed.
>> + @retval !0 Actual number of bytes written to serial device.
>> +
>> +**/
>> +UINTN
>> +EFIAPI
>> +SerialPortWrite (
>> + IN UINT8 *Buffer,
>> + IN UINTN NumberOfBytes
>> + )
>> +{
>> + XENCONS_RING_IDX Consumer, Producer;
>> + UINTN Sent;
>> +
>> + if (!mXenConsoleInterface) {
>> + return 0;
>> + }
>> +
>> + Consumer = mXenConsoleInterface->out_cons;
>> + Producer = mXenConsoleInterface->out_prod;
>> +
>> + MemoryFence ();
>> +
>> + Sent = 0;
>> + while (Sent < NumberOfBytes && ((Producer - Consumer) < sizeof
>> (mXenConsoleInterface->out)))
>> + mXenConsoleInterface->out[MASK_XENCONS_IDX(Producer++,
>> mXenConsoleInterface->out)] = Buffer[Sent++];
>> +
>> + MemoryFence ();
>> +
>> + mXenConsoleInterface->out_prod = Producer;
>> +
>> + if (Sent > 0) {
>> + XenHypercallEventChannelOp (EVTCHNOP_send, &mXenConsoleEventChain);
>> + }
>> +
>> + return Sent;
>> +}
>> +
>> +/**
>> + Read data from serial device and save the data in buffer.
>> +
>> + @param Buffer Point of data buffer which need to be written.
>> + @param NumberOfBytes Size of Buffer[].
>> +
>> + @retval 0 Read data failed.
>> + @retval !0 Actual number of bytes read from serial device.
>> +
>> +**/
>> +UINTN
>> +EFIAPI
>> +SerialPortRead (
>> + OUT UINT8 *Buffer,
>> + IN UINTN NumberOfBytes
>> +)
>> +{
>> + XENCONS_RING_IDX Consumer, Producer;
>> + UINTN Received;
>> +
>> + if (!mXenConsoleInterface) {
>> + return 0;
>> + }
>> +
>> + Consumer = mXenConsoleInterface->in_cons;
>> + Producer = mXenConsoleInterface->in_prod;
>> +
>> + MemoryFence ();
>> +
>> + Received = 0;
>> + while (Received < NumberOfBytes && Consumer < Producer)
>> + Buffer[Received++] =
>> mXenConsoleInterface->in[MASK_XENCONS_IDX(Consumer++,
>> mXenConsoleInterface->in)];
>> +
>> + MemoryFence ();
>> +
>> + mXenConsoleInterface->in_cons = Consumer;
>> +
>> + XenHypercallEventChannelOp (EVTCHNOP_send, &mXenConsoleEventChain);
>> +
>> + return Received;
>> +}
>> +
>> +/**
>> + Check to see if any data is available to be read from the debug device.
>> +
>> + @retval TRUE At least one byte of data is available to be read
>> + @retval FALSE No data is available to be read
>> +
>> +**/
>> +BOOLEAN
>> +EFIAPI
>> +SerialPortPoll (
>> + VOID
>> + )
>> +{
>> + return mXenConsoleInterface &&
>> + mXenConsoleInterface->in_cons != mXenConsoleInterface->in_prod;
>
> Do you need a memory barrier after reading in_cons and in_prod and
> before comparing them, to make sure that the view is consistent?
>
I don't think so. The memory reads both have to complete before the
comparison can be performed, and the comparison itself is not a memory
access.
>
>> +}
>> diff --git
>> a/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.inf
>> b/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.inf
>> new file mode 100644
>> index 000000000000..f7925b3e6bc3
>> --- /dev/null
>> +++ b/OvmfPkg/Library/XenConsoleSerialPortLib/XenConsoleSerialPortLib.inf
>> @@ -0,0 +1,34 @@
>> +#/** @file
>> +#
>> +# Component description file for XenConsoleSerialPortLib module
>> +#
>> +# Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR>
>> +#
>> +# This program and the accompanying materials
>> +# are licensed and made available under the terms and conditions of the
>> BSD License
>> +# which accompanies this distribution. The full text of the license may
>> be found at
>> +# http://opensource.org/licenses/bsd-license.php
>> +#
>> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
>> +# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR
>> IMPLIED.
>> +#
>> +#**/
>> +
>> +[Defines]
>> + INF_VERSION = 0x00010005
>> + BASE_NAME = XenConsoleSerialPortLib
>> + FILE_GUID = 401406DD-BCAC-4B91-9F4E-72A7FEBE4762
>> + MODULE_TYPE = BASE
>> + VERSION_STRING = 1.0
>> + LIBRARY_CLASS = SerialPortLib
>> +
>> +[Sources.common]
>> + XenConsoleSerialPortLib.c
>> +
>> +[LibraryClasses]
>> + BaseLib
>> + XenHypercallLib
>> +
>> +[Packages]
>> + MdePkg/MdePkg.dec
>> + OvmfPkg/OvmfPkg.dec
>> --
>> 1.8.3.2
>>
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