OvmfPkg/PvScsiDxe: Setup requests and completions rings

These rings are shared memory buffers between host and device in which
a cyclic buffer is managed to send request descriptors from host to
device and receive completion descriptors from device to host.

Note that because device may be constrained by IOMMU or guest may be run
under AMD SEV, we make sure to map these rings to device by using
PciIo->Map().

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2567
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Message-Id: <20200328200100.60786-14-liran.alon@oracle.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

OvmfPkg/PvScsiDxe/PvScsi.c

@@ -11,11 +11,13 @@
 
 #include <IndustryStandard/Pci.h>
 #include <IndustryStandard/PvScsi.h>
+#include <Library/BaseLib.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/UefiLib.h>
 #include <Protocol/PciIo.h>
+#include <Protocol/PciRootBridgeIo.h>
 #include <Uefi/UefiSpec.h>
 
 #include "PvScsi.h"
@@ -436,6 +438,207 @@ PvScsiRestorePciAttributes (
                 );
 }
 
+STATIC
+EFI_STATUS
+PvScsiAllocateSharedPages (
+  IN PVSCSI_DEV                     *Dev,
+  IN UINTN                          Pages,
+  OUT VOID                          **HostAddress,
+  OUT PVSCSI_DMA_DESC               *DmaDesc
+  )
+{
+  EFI_STATUS Status;
+  UINTN      NumberOfBytes;
+
+  Status = Dev->PciIo->AllocateBuffer (
+                         Dev->PciIo,
+                         AllocateAnyPages,
+                         EfiBootServicesData,
+                         Pages,
+                         HostAddress,
+                         EFI_PCI_ATTRIBUTE_MEMORY_CACHED
+                         );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  NumberOfBytes = EFI_PAGES_TO_SIZE (Pages);
+  Status = Dev->PciIo->Map (
+                         Dev->PciIo,
+                         EfiPciIoOperationBusMasterCommonBuffer,
+                         *HostAddress,
+                         &NumberOfBytes,
+                         &DmaDesc->DeviceAddress,
+                         &DmaDesc->Mapping
+                         );
+  if (EFI_ERROR (Status)) {
+    goto FreeBuffer;
+  }
+
+  if (NumberOfBytes != EFI_PAGES_TO_SIZE (Pages)) {
+    Status = EFI_OUT_OF_RESOURCES;
+    goto Unmap;
+  }
+
+  return EFI_SUCCESS;
+
+Unmap:
+  Dev->PciIo->Unmap (Dev->PciIo, DmaDesc->Mapping);
+
+FreeBuffer:
+  Dev->PciIo->FreeBuffer (Dev->PciIo, Pages, *HostAddress);
+
+  return Status;
+}
+
+STATIC
+VOID
+PvScsiFreeSharedPages (
+  IN PVSCSI_DEV                     *Dev,
+  IN UINTN                          Pages,
+  IN VOID                           *HostAddress,
+  IN PVSCSI_DMA_DESC                *DmaDesc
+  )
+{
+  Dev->PciIo->Unmap (Dev->PciIo, DmaDesc->Mapping);
+  Dev->PciIo->FreeBuffer (Dev->PciIo, Pages, HostAddress);
+}
+
+STATIC
+EFI_STATUS
+PvScsiInitRings (
+  IN OUT PVSCSI_DEV *Dev
+  )
+{
+  EFI_STATUS Status;
+  union {
+    PVSCSI_CMD_DESC_SETUP_RINGS Cmd;
+    UINT32                      Uint32;
+  } AlignedCmd;
+  PVSCSI_CMD_DESC_SETUP_RINGS *Cmd;
+
+  Cmd = &AlignedCmd.Cmd;
+
+  Status = PvScsiAllocateSharedPages (
+             Dev,
+             1,
+             (VOID **)&Dev->RingDesc.RingState,
+             &Dev->RingDesc.RingStateDmaDesc
+             );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+  ZeroMem (Dev->RingDesc.RingState, EFI_PAGE_SIZE);
+
+  Status = PvScsiAllocateSharedPages (
+             Dev,
+             1,
+             (VOID **)&Dev->RingDesc.RingReqs,
+             &Dev->RingDesc.RingReqsDmaDesc
+             );
+  if (EFI_ERROR (Status)) {
+    goto FreeRingState;
+  }
+  ZeroMem (Dev->RingDesc.RingReqs, EFI_PAGE_SIZE);
+
+  Status = PvScsiAllocateSharedPages (
+             Dev,
+             1,
+             (VOID **)&Dev->RingDesc.RingCmps,
+             &Dev->RingDesc.RingCmpsDmaDesc
+             );
+  if (EFI_ERROR (Status)) {
+    goto FreeRingReqs;
+  }
+  ZeroMem (Dev->RingDesc.RingCmps, EFI_PAGE_SIZE);
+
+  ZeroMem (Cmd, sizeof (*Cmd));
+  Cmd->ReqRingNumPages = 1;
+  Cmd->CmpRingNumPages = 1;
+  Cmd->RingsStatePPN = RShiftU64 (
+                         Dev->RingDesc.RingStateDmaDesc.DeviceAddress,
+                         EFI_PAGE_SHIFT
+                         );
+  Cmd->ReqRingPPNs[0] = RShiftU64 (
+                          Dev->RingDesc.RingReqsDmaDesc.DeviceAddress,
+                          EFI_PAGE_SHIFT
+                          );
+  Cmd->CmpRingPPNs[0] = RShiftU64 (
+                          Dev->RingDesc.RingCmpsDmaDesc.DeviceAddress,
+                          EFI_PAGE_SHIFT
+                          );
+
+  STATIC_ASSERT (
+    sizeof (*Cmd) % sizeof (UINT32) == 0,
+    "Cmd must be multiple of 32-bit words"
+    );
+  Status = PvScsiWriteCmdDesc (
+             Dev,
+             PvScsiCmdSetupRings,
+             (UINT32 *)Cmd,
+             sizeof (*Cmd) / sizeof (UINT32)
+             );
+  if (EFI_ERROR (Status)) {
+    goto FreeRingCmps;
+  }
+
+  return EFI_SUCCESS;
+
+FreeRingCmps:
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    Dev->RingDesc.RingCmps,
+    &Dev->RingDesc.RingCmpsDmaDesc
+    );
+
+FreeRingReqs:
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    Dev->RingDesc.RingReqs,
+    &Dev->RingDesc.RingReqsDmaDesc
+    );
+
+FreeRingState:
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    Dev->RingDesc.RingState,
+    &Dev->RingDesc.RingStateDmaDesc
+    );
+
+  return Status;
+}
+
+STATIC
+VOID
+PvScsiFreeRings (
+  IN OUT PVSCSI_DEV *Dev
+  )
+{
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    Dev->RingDesc.RingCmps,
+    &Dev->RingDesc.RingCmpsDmaDesc
+    );
+
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    Dev->RingDesc.RingReqs,
+    &Dev->RingDesc.RingReqsDmaDesc
+    );
+
+  PvScsiFreeSharedPages (
+    Dev,
+    1,
+    Dev->RingDesc.RingState,
+    &Dev->RingDesc.RingStateDmaDesc
+    );
+}
+
 STATIC
 EFI_STATUS
 PvScsiInit (
@@ -466,6 +669,14 @@ PvScsiInit (
     goto RestorePciAttributes;
   }
 
+  //
+  // Init PVSCSI rings
+  //
+  Status = PvScsiInitRings (Dev);
+  if (EFI_ERROR (Status)) {
+    goto RestorePciAttributes;
+  }
+
   //
   // Populate the exported interface's attributes
   //
@@ -509,6 +720,14 @@ PvScsiUninit (
   IN OUT PVSCSI_DEV *Dev
   )
 {
+  //
+  // Reset device to stop device usage of the rings.
+  // This is required to safely free the rings.
+  //
+  PvScsiResetAdapter (Dev);
+
+  PvScsiFreeRings (Dev);
+
   PvScsiRestorePciAttributes (Dev);
 }
 

OvmfPkg/PvScsiDxe/PvScsi.h

@@ -15,12 +15,29 @@
 #include <Library/DebugLib.h>
 #include <Protocol/ScsiPassThruExt.h>
 
+typedef struct {
+  EFI_PHYSICAL_ADDRESS DeviceAddress;
+  VOID                 *Mapping;
+} PVSCSI_DMA_DESC;
+
+typedef struct {
+  PVSCSI_RINGS_STATE   *RingState;
+  PVSCSI_DMA_DESC      RingStateDmaDesc;
+
+  PVSCSI_RING_REQ_DESC *RingReqs;
+  PVSCSI_DMA_DESC      RingReqsDmaDesc;
+
+  PVSCSI_RING_CMP_DESC *RingCmps;
+  PVSCSI_DMA_DESC      RingCmpsDmaDesc;
+} PVSCSI_RING_DESC;
+
 #define PVSCSI_SIG SIGNATURE_32 ('P', 'S', 'C', 'S')
 
 typedef struct {
   UINT32                          Signature;
   EFI_PCI_IO_PROTOCOL             *PciIo;
   UINT64                          OriginalPciAttributes;
+  PVSCSI_RING_DESC                RingDesc;
   UINT8                           MaxTarget;
   UINT8                           MaxLun;
   EFI_EXT_SCSI_PASS_THRU_PROTOCOL PassThru;

OvmfPkg/PvScsiDxe/PvScsiDxe.inf

@@ -26,6 +26,7 @@
   OvmfPkg/OvmfPkg.dec
 
 [LibraryClasses]
+  BaseLib
   BaseMemoryLib
   DebugLib
   MemoryAllocationLib