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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 Fri, 23 Jan 2015, Ard Biesheuvel wrote:
> 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.
I think that you are right
> >
> >> +}
> >> 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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