From: "Laszlo Ersek" <lersek@redhat.com>
To: devel@edk2.groups.io, anthony.perard@citrix.com
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Julien Grall <julien.grall@arm.com>,
Jordan Justen <jordan.l.justen@intel.com>,
xen-devel@lists.xenproject.org
Subject: Re: [edk2-devel] [PATCH 08/11] OvmfPkg/XenBus: Change XENBUS_PROTOCOL to not return allocated memory
Date: Mon, 16 Sep 2019 18:16:40 +0200 [thread overview]
Message-ID: <6c8ab94a-cc2b-9354-207c-620a3939e199@redhat.com> (raw)
In-Reply-To: <20190913145100.303433-9-anthony.perard@citrix.com>
On 09/13/19 16:50, Anthony PERARD wrote:
> XsRead and XsBackendRead of the XENBUS_PROTOCOL return allocated
> memory but this isn't allowed during the ExitBootServices call. We
> need XsRead and XsBackendRead to disconnect from the device so
> XENBUS_PROTOCOL is changed to use a buffer supplied by a child driver.
>
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2190
> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
> ---
> OvmfPkg/Include/Protocol/XenBus.h | 32 ++++++++++++----------
> OvmfPkg/XenBusDxe/XenStore.c | 44 +++++-------------------------
> OvmfPkg/XenBusDxe/XenStore.h | 6 +++--
> OvmfPkg/XenPvBlkDxe/BlockFront.c | 45 ++++++++++++++++++-------------
> 4 files changed, 54 insertions(+), 73 deletions(-)
>
> diff --git a/OvmfPkg/Include/Protocol/XenBus.h b/OvmfPkg/Include/Protocol/XenBus.h
> index 8ff5ca3575..c22bdfb368 100644
> --- a/OvmfPkg/Include/Protocol/XenBus.h
> +++ b/OvmfPkg/Include/Protocol/XenBus.h
> @@ -35,6 +35,12 @@ typedef struct
>
> #define XST_NIL ((XENSTORE_TRANSACTION *) NULL)
>
> +//
> +// When reading a node from xenstore, if the size of the data to be read is
> +// unknown, this value can be use for the size of the buffer.
> +//
> +#define XENSTORE_PAYLOAD_MAX 4096
> +
This macro is already defined in "IndustryStandard/Xen/io/xs_wire.h".
Can we get it from there?
The extra documentation is OK, of course (replacing "this value" with
"XENSTORE_PAYLOAD_MAX").
Other than that, I'm going to have to ACK this after a brief skim only.
Acked-by: Laszlo Ersek <lersek@redhat.com>
Thanks
Laszlo
> typedef enum {
> XENSTORE_STATUS_SUCCESS = 0,
> XENSTORE_STATUS_FAIL,
> @@ -64,19 +70,17 @@ typedef enum {
> ///
>
> /**
> - Get the contents of the node Node of the PV device. Returns the contents in
> - *Result which should be freed after use.
> + Get the contents of the node Node of the PV device.
>
> @param This A pointer to XENBUS_PROTOCOL instance.
> @param Transaction The XenStore transaction covering this request.
> @param Node The basename of the file to read.
> - @param Result The returned contents from this file.
> + @param BufferSize On input, a pointer to the size of the buffer at Buffer.
> + On output, the size of the data written to Buffer.
> + @param Buffer A pointer to a buffer into which the data read will be saved.
>
> @return On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
> indicating the type of failure.
> -
> - @note The results buffer is malloced and should be free'd by the
> - caller.
> **/
> typedef
> XENSTORE_STATUS
> @@ -84,23 +88,22 @@ XENSTORE_STATUS
> IN XENBUS_PROTOCOL *This,
> IN CONST XENSTORE_TRANSACTION *Transaction,
> IN CONST CHAR8 *Node,
> - OUT VOID **Result
> + IN OUT UINTN *BufferSize,
> + OUT VOID *Buffer
> );
>
> /**
> - Get the contents of the node Node of the PV device's backend. Returns the
> - contents in *Result which should be freed after use.
> + Get the contents of the node Node of the PV device's backend.
>
> @param This A pointer to XENBUS_PROTOCOL instance.
> @param Transaction The XenStore transaction covering this request.
> @param Node The basename of the file to read.
> - @param Result The returned contents from this file.
> + @param BufferSize On input, a pointer to the size of the buffer at Buffer.
> + On output, the size of the data written to Buffer.
> + @param Buffer A pointer to a buffer into which the data read will be saved.
>
> @return On success, XENSTORE_STATUS_SUCCESS. Otherwise an errno value
> indicating the type of failure.
> -
> - @note The results buffer is malloced and should be free'd by the
> - caller.
> **/
> typedef
> XENSTORE_STATUS
> @@ -108,7 +111,8 @@ XENSTORE_STATUS
> IN XENBUS_PROTOCOL *This,
> IN CONST XENSTORE_TRANSACTION *Transaction,
> IN CONST CHAR8 *Node,
> - OUT VOID **Result
> + IN OUT UINTN *BufferSize,
> + OUT VOID *Buffer
> );
>
> /**
> diff --git a/OvmfPkg/XenBusDxe/XenStore.c b/OvmfPkg/XenBusDxe/XenStore.c
> index b9588bb8c6..cb2d9e1215 100644
> --- a/OvmfPkg/XenBusDxe/XenStore.c
> +++ b/OvmfPkg/XenBusDxe/XenStore.c
> @@ -1336,27 +1336,11 @@ XenBusXenStoreRead (
> IN XENBUS_PROTOCOL *This,
> IN CONST XENSTORE_TRANSACTION *Transaction,
> IN CONST CHAR8 *Node,
> - OUT VOID **Value
> + IN OUT UINTN *BufferSize,
> + OUT VOID *Buffer
> )
> {
> - XENSTORE_STATUS Status;
> - UINTN BufferSize;
> - VOID *Buffer;
> -
> - BufferSize = XENSTORE_PAYLOAD_MAX + 1;
> - Buffer = AllocatePool (BufferSize);
> - if (Buffer == NULL) {
> - return XENSTORE_STATUS_ENOMEM;
> - }
> -
> - Status = XenStoreRead (Transaction, This->Node, Node, &BufferSize, Buffer);
> -
> - if (Status == XENSTORE_STATUS_SUCCESS) {
> - *Value = Buffer;
> - } else {
> - FreePool (Buffer);
> - }
> - return Status;
> + return XenStoreRead (Transaction, This->Node, Node, BufferSize, Buffer);
> }
>
> XENSTORE_STATUS
> @@ -1365,27 +1349,11 @@ XenBusXenStoreBackendRead (
> IN XENBUS_PROTOCOL *This,
> IN CONST XENSTORE_TRANSACTION *Transaction,
> IN CONST CHAR8 *Node,
> - OUT VOID **Value
> + IN OUT UINTN *BufferSize,
> + OUT VOID *Buffer
> )
> {
> - XENSTORE_STATUS Status;
> - UINTN BufferSize;
> - VOID *Buffer;
> -
> - BufferSize = XENSTORE_PAYLOAD_MAX + 1;
> - Buffer = AllocatePool (BufferSize);
> - if (Buffer == NULL) {
> - return XENSTORE_STATUS_ENOMEM;
> - }
> -
> - Status = XenStoreRead (Transaction, This->Backend, Node, &BufferSize, Buffer);
> -
> - if (Status == XENSTORE_STATUS_SUCCESS) {
> - *Value = Buffer;
> - } else {
> - FreePool (Buffer);
> - }
> - return Status;
> + return XenStoreRead (Transaction, This->Backend, Node, BufferSize, Buffer);
> }
>
> XENSTORE_STATUS
> diff --git a/OvmfPkg/XenBusDxe/XenStore.h b/OvmfPkg/XenBusDxe/XenStore.h
> index 13f7d132e6..ca8c080433 100644
> --- a/OvmfPkg/XenBusDxe/XenStore.h
> +++ b/OvmfPkg/XenBusDxe/XenStore.h
> @@ -289,7 +289,8 @@ XenBusXenStoreRead (
> IN XENBUS_PROTOCOL *This,
> IN CONST XENSTORE_TRANSACTION *Transaction,
> IN CONST CHAR8 *Node,
> - OUT VOID **Value
> + IN OUT UINTN *BufferSize,
> + OUT VOID *Buffer
> );
>
> XENSTORE_STATUS
> @@ -298,7 +299,8 @@ XenBusXenStoreBackendRead (
> IN XENBUS_PROTOCOL *This,
> IN CONST XENSTORE_TRANSACTION *Transaction,
> IN CONST CHAR8 *Node,
> - OUT VOID **Value
> + IN OUT UINTN *BufferSize,
> + OUT VOID *Buffer
> );
>
> XENSTORE_STATUS
> diff --git a/OvmfPkg/XenPvBlkDxe/BlockFront.c b/OvmfPkg/XenPvBlkDxe/BlockFront.c
> index 8dca4c82f0..25a398ccc4 100644
> --- a/OvmfPkg/XenPvBlkDxe/BlockFront.c
> +++ b/OvmfPkg/XenPvBlkDxe/BlockFront.c
> @@ -41,19 +41,22 @@ XenBusReadUint64 (
> )
> {
> XENSTORE_STATUS Status;
> - CHAR8 *Ptr;
> + CHAR8 Buffer[22];
> + UINTN BufferSize;
> +
> + BufferSize = sizeof (Buffer) - 1;
>
> if (!FromBackend) {
> - Status = This->XsRead (This, XST_NIL, Node, (VOID**)&Ptr);
> + Status = This->XsRead (This, XST_NIL, Node, &BufferSize, Buffer);
> } else {
> - Status = This->XsBackendRead (This, XST_NIL, Node, (VOID**)&Ptr);
> + Status = This->XsBackendRead (This, XST_NIL, Node, &BufferSize, Buffer);
> }
> if (Status != XENSTORE_STATUS_SUCCESS) {
> return Status;
> }
> + Buffer[BufferSize] = '\0';
> // AsciiStrDecimalToUint64 will ASSERT if Ptr overflow UINT64.
> - *ValuePtr = AsciiStrDecimalToUint64 (Ptr);
> - FreePool (Ptr);
> + *ValuePtr = AsciiStrDecimalToUint64 (Buffer);
> return Status;
> }
>
> @@ -143,43 +146,47 @@ XenPvBlockFrontInitialization (
> OUT XEN_BLOCK_FRONT_DEVICE **DevPtr
> )
> {
> - XENSTORE_TRANSACTION Transaction;
> - CHAR8 *DeviceType;
> - blkif_sring_t *SharedRing;
> - XENSTORE_STATUS Status;
> + XENSTORE_TRANSACTION Transaction;
> + CHAR8 Buffer[XENSTORE_PAYLOAD_MAX + 1];
> + UINTN BufferSize;
> + blkif_sring_t *SharedRing;
> + XENSTORE_STATUS Status;
> XEN_BLOCK_FRONT_DEVICE *Dev;
> - XenbusState State;
> - UINT64 Value;
> - CHAR8 *Params;
> + XenbusState State;
> + UINT64 Value;
>
> ASSERT (NodeName != NULL);
>
> + BufferSize = sizeof (Buffer) - 1;
> +
> Dev = AllocateZeroPool (sizeof (XEN_BLOCK_FRONT_DEVICE));
> Dev->Signature = XEN_BLOCK_FRONT_SIGNATURE;
> Dev->NodeName = NodeName;
> Dev->XenBusIo = XenBusIo;
> Dev->DeviceId = XenBusIo->DeviceId;
>
> - XenBusIo->XsRead (XenBusIo, XST_NIL, "device-type", (VOID**)&DeviceType);
> - if (AsciiStrCmp (DeviceType, "cdrom") == 0) {
> + BufferSize = sizeof (Buffer) - 1;
> + XenBusIo->XsRead (XenBusIo, XST_NIL, "device-type", &BufferSize, Buffer);
> + Buffer[BufferSize] = '\0';
> + if (AsciiStrCmp (Buffer, "cdrom") == 0) {
> Dev->MediaInfo.CdRom = TRUE;
> } else {
> Dev->MediaInfo.CdRom = FALSE;
> }
> - FreePool (DeviceType);
>
> if (Dev->MediaInfo.CdRom) {
> - Status = XenBusIo->XsBackendRead (XenBusIo, XST_NIL, "params", (VOID**)&Params);
> + BufferSize = sizeof (Buffer) - 1;
> + Status = XenBusIo->XsBackendRead (XenBusIo, XST_NIL, "params",
> + &BufferSize, Buffer);
> if (Status != XENSTORE_STATUS_SUCCESS) {
> DEBUG ((EFI_D_ERROR, "%a: Failed to read params (%d)\n", __FUNCTION__, Status));
> goto Error;
> }
> - if (AsciiStrLen (Params) == 0 || AsciiStrCmp (Params, "aio:") == 0) {
> - FreePool (Params);
> + Buffer[BufferSize] = '\0';
> + if (AsciiStrLen (Buffer) == 0 || AsciiStrCmp (Buffer, "aio:") == 0) {
> DEBUG ((EFI_D_INFO, "%a: Empty cdrom\n", __FUNCTION__));
> goto Error;
> }
> - FreePool (Params);
> }
>
> Status = XenBusReadUint64 (XenBusIo, "backend-id", FALSE, &Value);
>
next prev parent reply other threads:[~2019-09-16 16:16 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-13 14:50 [PATCH 00/11] OvmfPkg/XenBusDxe: Fix ExitBootServices handler to avoid allocation Anthony PERARD
2019-09-13 14:50 ` [PATCH 01/11] OvmfPkg/XenBusDxe: Fix missing \n in DEBUG messages Anthony PERARD
2019-09-16 14:24 ` [edk2-devel] " Laszlo Ersek
2019-09-13 14:50 ` [PATCH 02/11] OvmfPkg/XenBusDxe: Have XenStoreFindWatch take a pointer Anthony PERARD
2019-09-16 14:38 ` [edk2-devel] " Laszlo Ersek
2019-09-13 14:50 ` [PATCH 03/11] OvmfPkg/XenBusDxe: Rework watch events reception Anthony PERARD
2019-09-16 14:39 ` [edk2-devel] " Laszlo Ersek
2019-09-13 14:50 ` [PATCH 04/11] OvmfPkg/XenBusDxe: Avoid Allocate in XenStoreVSPrint Anthony PERARD
2019-09-16 14:45 ` [edk2-devel] " Laszlo Ersek
2019-09-13 14:50 ` [PATCH 05/11] OvmfPkg/XenBusDxe: Construct paths without allocation Anthony PERARD
2019-09-16 15:39 ` [edk2-devel] " Laszlo Ersek
2019-09-16 15:43 ` Laszlo Ersek
2019-09-13 14:50 ` [PATCH 06/11] OvmfPkg/XenBusDxe: Rework XenStoreProcessMessage to avoid allocating memory Anthony PERARD
2019-09-16 15:41 ` [edk2-devel] " Laszlo Ersek
2019-09-13 14:50 ` [PATCH 07/11] OvmfPkg/XenBusDxe: Use on stack buffer in internal functions Anthony PERARD
2019-09-16 16:11 ` [edk2-devel] " Laszlo Ersek
2019-09-13 14:50 ` [PATCH 08/11] OvmfPkg/XenBus: Change XENBUS_PROTOCOL to not return allocated memory Anthony PERARD
2019-09-16 16:16 ` Laszlo Ersek [this message]
2019-09-13 14:50 ` [PATCH 09/11] OvmfPkg/XenBusDxe: Fix NotifyExitBoot to avoid Memory Allocation Services Anthony PERARD
2019-09-16 17:36 ` [edk2-devel] " Laszlo Ersek
2019-09-16 18:36 ` Andrew Fish
2019-09-16 19:31 ` Laszlo Ersek
2019-09-16 20:50 ` Andrew Fish
2019-09-13 14:50 ` [PATCH 10/11] OvmfPkg/XenPvBlkDxe: Use XenBusIo->RegisterExitCallback Anthony PERARD
2019-09-13 14:51 ` [PATCH 11/11] OvmfPkg/XenBusDxe: Fix XenStoreWaitForEvent use during EBS Anthony PERARD
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