On 11/29/18 00:06, Ard Biesheuvel wrote: > On Wed, 28 Nov 2018 at 23:54, Laszlo Ersek <[email protected]> wrote: >> >> On 11/28/18 20:16, Ard Biesheuvel wrote: >>> The primary FV contains the firmware boot image, which is not >>> runtime updatable in our case. So exposing it to the NOR flash >>> driver is undesirable, since it may attempt to modify the NOR >>> flash contents. >> >> With you so far. >> >>> It is also rather pointless, since we don't >>> keep anything there that we don't already expose via the FVB >>> protocol instances that DXE core creates for us based on the >>> FV HOBs >> >> I don't follow -- the DXE core does rely on the FV HOBs that we create for >> it, but I don't remember the DXE core creating FVB protocol instances. An >> FVB ("firmware volume block") protocol instance is usually created by a >> flash driver. What am I missing? >> >> Do you mean handles with MemoryMapped(...)/FvFile(...) and >> Fv(...)/FvFile(...) device paths on them? That point into firmware volumes >> (that have been supposedly decompressed from flash to RAM)? >> > > The DXE core dispatcher calls CoreProcessFvImageFile() for all FV > images it encounters, but looking closer, that only happens for > embedded FV images, not the primary one. > > But that still means the primary FV contains nothing we actually need.
OK; I missed CoreProcessFvImageFile(). Even though it's specified in Vol2, "10.4 Firmware Volume Image Files", of the PI-1.6 spec. Thanks Laszlo > >>> (and so there is nothing the partition or file system >>> drivers could potentially attach to via the block I/O and disk >>> I/O protocol instances that the NOR flash driver creates) >> >> Ugh, NorFlashDxe creates BlockIo and DiskIo interfaces itself??? >> >> Let's see... >> >> /* >> Although DiskIoDxe will automatically install the DiskIO protocol whenever >> we install the BlockIO protocol, its implementation is sub-optimal as it >> reads >> and writes entire blocks using the BlockIO protocol. In fact we can access >> NOR flash with a finer granularity than that, so we can improve performance >> by directly producing the DiskIO protocol. >> */ >> >> Umm... this flash driver does a lot more than I thought it did... or should. >> :) >> >> >> Anyway I think it should suffice to say in the commit message that we don't >> want to expose the first flash device as an FVB protocol instance, because >> (a) it's read-only, and (b) in the DXE phase, we don't use anything from >> that flash device. It contains: >> - the reset vector, >> - the SEC module, >> - (for ArmVirtQemu) the non-compressed PEI core, and PEIMs, >> - and a compressed bunch of DXE modules (incl. the DXE core) which are >> decompressed to RAM anyway. >> >>> So let's disregard the NOR flash block that covers the primary >>> FV. >> >> OK. >> >>> >>> Contributed-under: TianoCore Contribution Agreement 1.1 >>> Signed-off-by: Ard Biesheuvel <[email protected]> >>> --- >>> ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf | 5 +++++ >>> ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c | 13 +++++++++++-- >>> 2 files changed, 16 insertions(+), 2 deletions(-) >>> >>> diff --git a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf >>> b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf >>> index d86ff36dbd58..c5752a243e6b 100644 >>> --- a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf >>> +++ b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf >>> @@ -28,6 +28,7 @@ [Sources.common] >>> [Packages] >>> MdePkg/MdePkg.dec >>> ArmPlatformPkg/ArmPlatformPkg.dec >>> + ArmPkg/ArmPkg.dec >>> ArmVirtPkg/ArmVirtPkg.dec >>> >>> [LibraryClasses] >>> @@ -40,3 +41,7 @@ [Protocols] >>> >>> [Depex] >>> gFdtClientProtocolGuid >>> + >>> +[Pcd] >>> + gArmTokenSpaceGuid.PcdFvBaseAddress >>> + gArmTokenSpaceGuid.PcdFvSize >>> diff --git a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c >>> b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c >>> index 2678f57eaaad..72b47bdb5a78 100644 >>> --- a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c >>> +++ b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c >>> @@ -75,13 +75,22 @@ NorFlashPlatformGetDevices ( >>> Size = SwapBytes64 (ReadUnaligned64 ((VOID *)&Reg[2])); >>> Reg += 4; >>> >>> + PropSize -= 4 * sizeof (UINT32); >>> + >>> + // >>> + // Disregard any flash devices that overlap with the primary FV. >>> + // The firmware is not updatable from inside the guest anyway. >>> + // >>> + if ((PcdGet64 (PcdFvBaseAddress) + PcdGet32 (PcdFvSize) >= Base) && >>> + (Base + Size) >= PcdGet64 (PcdFvBaseAddress)) { >>> + continue; >>> + } >>> + >> >> The overlap condition is expressed correctly, in general, I think; however, >> both subconditions are off-by-one each. In each, we compare an exclusive >> limit (one's end) with an inclusive limit (the other's base). And, when >> exclusive equals inclusive, there is no overlap; they are directly adjacent >> only. I'd drop the equal signs. >> >> >>> mNorFlashDevices[Num].DeviceBaseAddress = (UINTN)Base; >>> mNorFlashDevices[Num].RegionBaseAddress = (UINTN)Base; >>> mNorFlashDevices[Num].Size = (UINTN)Size; >>> mNorFlashDevices[Num].BlockSize = QEMU_NOR_BLOCK_SIZE; >>> Num++; >>> - >>> - PropSize -= 4 * sizeof (UINT32); >>> } >>> } >>> >>> >> >> Thanks >> Laszlo _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
