ArmVirtPkg/PlatformBootManagerLib: connect Virtio RNG devices again

Virtio RNG devices are never boot devices, so in commit ff1d0fbfbaec we
stopped connecting them. This is a problem because an OS boot loader may
depend on EFI_RNG_PROTOCOL to seed the OS's RNG.

Connect Virtio RNG devices again. And, while commit ff1d0fbfbaec removed
that from PlatformBootManagerAfterConsole(), reintroduce it now to
PlatformBootManagerBeforeConsole() -- this way Driver#### options launched
between both functions may access EFI_RNG_PROTOCOL too.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: ff1d0fbfbaec55038ccf888759588fa4e21516f4
Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1579518
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

2 files changed, 130 insertions, 0 deletions

diff --git a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
index 5d5e51d8c8..62cce6a01e 100644
--- a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
+++ b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBm.c
@@ -16,6 +16,7 @@
 **/

 

 #include <IndustryStandard/Pci22.h>

+#include <IndustryStandard/Virtio095.h>

 #include <Library/BootLogoLib.h>

 #include <Library/DevicePathLib.h>

 #include <Library/PcdLib.h>

@@ -27,6 +28,7 @@
 #include <Protocol/LoadedImage.h>

 #include <Protocol/PciIo.h>

 #include <Protocol/PciRootBridgeIo.h>

+#include <Protocol/VirtioDevice.h>

 #include <Guid/EventGroup.h>

 #include <Guid/RootBridgesConnectedEventGroup.h>

 

@@ -261,6 +263,121 @@ IsPciDisplay (
 

 

 /**

+  This FILTER_FUNCTION checks if a handle corresponds to a Virtio RNG device at

+  the VIRTIO_DEVICE_PROTOCOL level.

+**/

+STATIC

+BOOLEAN

+EFIAPI

+IsVirtioRng (

+  IN EFI_HANDLE   Handle,

+  IN CONST CHAR16 *ReportText

+  )

+{

+  EFI_STATUS             Status;

+  VIRTIO_DEVICE_PROTOCOL *VirtIo;

+

+  Status = gBS->HandleProtocol (Handle, &gVirtioDeviceProtocolGuid,

+                  (VOID**)&VirtIo);

+  if (EFI_ERROR (Status)) {

+    return FALSE;

+  }

+  return (BOOLEAN)(VirtIo->SubSystemDeviceId ==

+                   VIRTIO_SUBSYSTEM_ENTROPY_SOURCE);

+}

+

+

+/**

+  This FILTER_FUNCTION checks if a handle corresponds to a Virtio RNG device at

+  the EFI_PCI_IO_PROTOCOL level.

+**/

+STATIC

+BOOLEAN

+EFIAPI

+IsVirtioPciRng (

+  IN EFI_HANDLE   Handle,

+  IN CONST CHAR16 *ReportText

+  )

+{

+  EFI_STATUS          Status;

+  EFI_PCI_IO_PROTOCOL *PciIo;

+  UINT16              VendorId;

+  UINT16              DeviceId;

+  UINT8               RevisionId;

+  BOOLEAN             Virtio10;

+  UINT16              SubsystemId;

+

+  Status = gBS->HandleProtocol (Handle, &gEfiPciIoProtocolGuid,

+                  (VOID**)&PciIo);

+  if (EFI_ERROR (Status)) {

+    return FALSE;

+  }

+

+  //

+  // Read and check VendorId.

+  //

+  Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint16, PCI_VENDOR_ID_OFFSET,

+                        1, &VendorId);

+  if (EFI_ERROR (Status)) {

+    goto PciError;

+  }

+  if (VendorId != VIRTIO_VENDOR_ID) {

+    return FALSE;

+  }

+

+  //

+  // Read DeviceId and RevisionId.

+  //

+  Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint16, PCI_DEVICE_ID_OFFSET,

+                        1, &DeviceId);

+  if (EFI_ERROR (Status)) {

+    goto PciError;

+  }

+  Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint8, PCI_REVISION_ID_OFFSET,

+                        1, &RevisionId);

+  if (EFI_ERROR (Status)) {

+    goto PciError;

+  }

+

+  //

+  // From DeviceId and RevisionId, determine whether the device is a

+  // modern-only Virtio 1.0 device. In case of Virtio 1.0, DeviceId can

+  // immediately be restricted to VIRTIO_SUBSYSTEM_ENTROPY_SOURCE, and

+  // SubsystemId will only play a sanity-check role. Otherwise, DeviceId can

+  // only be sanity-checked, and SubsystemId will decide.

+  //

+  if (DeviceId == 0x1040 + VIRTIO_SUBSYSTEM_ENTROPY_SOURCE &&

+      RevisionId >= 0x01) {

+    Virtio10 = TRUE;

+  } else if (DeviceId >= 0x1000 && DeviceId <= 0x103F && RevisionId == 0x00) {

+    Virtio10 = FALSE;

+  } else {

+    return FALSE;

+  }

+

+  //

+  // Read and check SubsystemId as dictated by Virtio10.

+  //

+  Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint16,

+                        PCI_SUBSYSTEM_ID_OFFSET, 1, &SubsystemId);

+  if (EFI_ERROR (Status)) {

+    goto PciError;

+  }

+  if (Virtio10 && SubsystemId >= 0x40) {

+    return TRUE;

+  }

+  if (!Virtio10 && SubsystemId == VIRTIO_SUBSYSTEM_ENTROPY_SOURCE) {

+    return TRUE;

+  }

+  return FALSE;

+

+PciError:

+  DEBUG ((DEBUG_ERROR, "%a: %s: %r\n", __FUNCTION__, ReportText, Status));

+  return FALSE;

+}

+

+

+/**

   This CALLBACK_FUNCTION attempts to connect a handle non-recursively, asking

   the matching driver to produce all first-level child handles.

 **/

@@ -644,6 +761,18 @@ PlatformBootManagerBeforeConsole (
   // Register platform-specific boot options and keyboard shortcuts.

   //

   PlatformRegisterOptionsAndKeys ();

+

+  //

+  // At this point, VIRTIO_DEVICE_PROTOCOL instances exist only for Virtio MMIO

+  // transports. Install EFI_RNG_PROTOCOL instances on Virtio MMIO RNG devices.

+  //

+  FilterAndProcess (&gVirtioDeviceProtocolGuid, IsVirtioRng, Connect);

+

+  //

+  // Install both VIRTIO_DEVICE_PROTOCOL and (dependent) EFI_RNG_PROTOCOL

+  // instances on Virtio PCI RNG devices.

+  //

+  FilterAndProcess (&gEfiPciIoProtocolGuid, IsVirtioPciRng, Connect);

 }

 

 /**

diff --git a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
index 1e22f8bb38..d6c1ef95dc 100644
--- a/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
+++ b/ArmVirtPkg/Library/PlatformBootManagerLib/PlatformBootManagerLib.inf
@@ -83,3 +83,4 @@
   gEfiLoadedImageProtocolGuid

   gEfiPciRootBridgeIoProtocolGuid

   gEfiSimpleFileSystemProtocolGuid

+  gVirtioDeviceProtocolGuid