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OvmfPkg/PvScsiDxe: Introduce DMA communication buffer

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In case device is constrained by IOMMU or guest is running under AMD SEV,
input/output buffers provided to device (DataBuffer and SenseData) needs
to be explicitly mapped to device by PciIo->Map().

To avoid the overhead of mapping/unmapping the DataBuffer and SenseData
to the device for every SCSI requst (and to simplify code), introduce a
single DMA communication buffer that will be mapped to device on
initialization. When a SCSI request needs to be sent to device, the
DataBuffer and SenseData will be copied from/to the DMA communication
buffer as required. This will be done by the following commits.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2567
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Message-Id: <20200328200100.60786-15-liran.alon@oracle.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Liran Alon
2020-03-28 23:00:57 +03:00
committed by mergify[bot]
parent b654edec03
commit 6510e19794
2 changed files with 58 additions and 2 deletions
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20
OvmfPkg/PvScsiDxe/PvScsi.h
View File

@@ -31,6 +31,21 @@ typedef struct {
PVSCSI_DMA_DESC RingCmpsDmaDesc;
} PVSCSI_RING_DESC;
typedef struct {
//
// As EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET.SenseDataLength is defined
// as UINT8, defining here SenseData size to MAX_UINT8 will guarantee it
// cannot overflow when passed to device.
//
UINT8 SenseData[MAX_UINT8];
//
// This size of the data is arbitrarily chosen.
// It seems to be sufficient for all I/O requests sent through
// EFI_SCSI_PASS_THRU_PROTOCOL.PassThru() for common boot scenarios.
//
UINT8 Data[0x2000];
} PVSCSI_DMA_BUFFER;
#define PVSCSI_SIG SIGNATURE_32 ('P', 'S', 'C', 'S')
typedef struct {
@@ -38,6 +53,8 @@ typedef struct {
EFI_PCI_IO_PROTOCOL *PciIo;
UINT64 OriginalPciAttributes;
PVSCSI_RING_DESC RingDesc;
PVSCSI_DMA_BUFFER *DmaBuf;
PVSCSI_DMA_DESC DmaBufDmaDesc;
UINT8 MaxTarget;
UINT8 MaxLun;
EFI_EXT_SCSI_PASS_THRU_PROTOCOL PassThru;
@@ -47,4 +64,7 @@ typedef struct {
#define PVSCSI_FROM_PASS_THRU(PassThruPointer) \
CR (PassThruPointer, PVSCSI_DEV, PassThru, PVSCSI_SIG)
#define PVSCSI_DMA_BUF_DEV_ADDR(Dev, MemberName) \
(Dev->DmaBufDmaDesc.DeviceAddress + OFFSET_OF(PVSCSI_DMA_BUFFER, MemberName))
#endif // __PVSCSI_DXE_H_