Re: [PATCH v4 3/5] OvmfPkg/PlatformInitLib: Add PlatformAddHobCB

["Ard Biesheuvel" <ardb@kernel.org>]

On Tue, 17 Jan 2023 at 16:03, Laszlo Ersek <lersek@redhat.com> wrote:
>
> On 1/17/23 13:16, Gerd Hoffmann wrote:
> > Add PlatformAddHobCB() callback function for use with
> > PlatformScanE820().  It adds HOBs for high memory and reservations (low
> > memory is handled elsewhere because there are some special cases to
> > consider).  This replaces calls to PlatformScanOrAdd64BitE820Ram() with
> > AddHighHobs = TRUE.
> >
> > Write any actions done (adding HOBs, skip unknown types) to the firmware
> > log with INFO loglevel.
> >
> > Also remove PlatformScanOrAdd64BitE820Ram() which is not used any more.
> >
> > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > ---
> >  OvmfPkg/Library/PlatformInitLib/MemDetect.c | 185 +++++---------------
> >  1 file changed, 47 insertions(+), 138 deletions(-)
> >
> > diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
> > index dfaa05a1c24f..c626fc49cf6c 100644
> > --- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c
> > +++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c
> > @@ -112,143 +112,6 @@ PlatformQemuUc32BaseInitialization (
> >    }
> >  }
> >
> > -/**
> > -  Iterate over the RAM entries in QEMU's fw_cfg E820 RAM map that start outside
> > -  of the 32-bit address range.
> > -
> > -  Find the highest exclusive >=4GB RAM address, or produce memory resource
> > -  descriptor HOBs for RAM entries that start at or above 4GB.
> > -
> > -  @param[out] MaxAddress  If MaxAddress is NULL, then PlatformScanOrAdd64BitE820Ram()
> > -                          produces memory resource descriptor HOBs for RAM
> > -                          entries that start at or above 4GB.
> > -
> > -                          Otherwise, MaxAddress holds the highest exclusive
> > -                          >=4GB RAM address on output. If QEMU's fw_cfg E820
> > -                          RAM map contains no RAM entry that starts outside of
> > -                          the 32-bit address range, then MaxAddress is exactly
> > -                          4GB on output.
> > -
> > -  @retval EFI_SUCCESS         The fw_cfg E820 RAM map was found and processed.
> > -
> > -  @retval EFI_PROTOCOL_ERROR  The RAM map was found, but its size wasn't a
> > -                              whole multiple of sizeof(EFI_E820_ENTRY64). No
> > -                              RAM entry was processed.
> > -
> > -  @return                     Error codes from QemuFwCfgFindFile(). No RAM
> > -                              entry was processed.
> > -**/
> > -STATIC
> > -EFI_STATUS
> > -PlatformScanOrAdd64BitE820Ram (
> > -  IN BOOLEAN  AddHighHob,
> > -  OUT UINT64  *LowMemory OPTIONAL,
> > -  OUT UINT64  *MaxAddress OPTIONAL
> > -  )
> > -{
> > -  EFI_STATUS            Status;
> > -  FIRMWARE_CONFIG_ITEM  FwCfgItem;
> > -  UINTN                 FwCfgSize;
> > -  EFI_E820_ENTRY64      E820Entry;
> > -  UINTN                 Processed;
> > -
> > -  Status = QemuFwCfgFindFile ("etc/e820", &FwCfgItem, &FwCfgSize);
> > -  if (EFI_ERROR (Status)) {
> > -    return Status;
> > -  }
> > -
> > -  if (FwCfgSize % sizeof E820Entry != 0) {
> > -    return EFI_PROTOCOL_ERROR;
> > -  }
> > -
> > -  if (LowMemory != NULL) {
> > -    *LowMemory = 0;
> > -  }
> > -
> > -  if (MaxAddress != NULL) {
> > -    *MaxAddress = BASE_4GB;
> > -  }
> > -
> > -  QemuFwCfgSelectItem (FwCfgItem);
> > -  for (Processed = 0; Processed < FwCfgSize; Processed += sizeof E820Entry) {
> > -    QemuFwCfgReadBytes (sizeof E820Entry, &E820Entry);
> > -    DEBUG ((
> > -      DEBUG_VERBOSE,
> > -      "%a: Base=0x%Lx Length=0x%Lx Type=%u\n",
> > -      __FUNCTION__,
> > -      E820Entry.BaseAddr,
> > -      E820Entry.Length,
> > -      E820Entry.Type
> > -      ));
> > -    if (E820Entry.Type == EfiAcpiAddressRangeMemory) {
> > -      if (AddHighHob && (E820Entry.BaseAddr >= BASE_4GB)) {
> > -        UINT64  Base;
> > -        UINT64  End;
> > -
> > -        //
> > -        // Round up the start address, and round down the end address.
> > -        //
> > -        Base = ALIGN_VALUE (E820Entry.BaseAddr, (UINT64)EFI_PAGE_SIZE);
> > -        End  = (E820Entry.BaseAddr + E820Entry.Length) &
> > -               ~(UINT64)EFI_PAGE_MASK;
> > -        if (Base < End) {
> > -          PlatformAddMemoryRangeHob (Base, End);
> > -          DEBUG ((
> > -            DEBUG_VERBOSE,
> > -            "%a: PlatformAddMemoryRangeHob [0x%Lx, 0x%Lx)\n",
> > -            __FUNCTION__,
> > -            Base,
> > -            End
> > -            ));
> > -        }
> > -      }
> > -
> > -      if (MaxAddress || LowMemory) {
> > -        UINT64  Candidate;
> > -
> > -        Candidate = E820Entry.BaseAddr + E820Entry.Length;
> > -        if (MaxAddress && (Candidate > *MaxAddress)) {
> > -          *MaxAddress = Candidate;
> > -          DEBUG ((
> > -            DEBUG_VERBOSE,
> > -            "%a: MaxAddress=0x%Lx\n",
> > -            __FUNCTION__,
> > -            *MaxAddress
> > -            ));
> > -        }
> > -
> > -        if (LowMemory && (Candidate > *LowMemory) && (Candidate < BASE_4GB)) {
> > -          *LowMemory = Candidate;
> > -          DEBUG ((
> > -            DEBUG_VERBOSE,
> > -            "%a: LowMemory=0x%Lx\n",
> > -            __FUNCTION__,
> > -            *LowMemory
> > -            ));
> > -        }
> > -      }
> > -    } else if (E820Entry.Type == EfiAcpiAddressRangeReserved) {
> > -      if (AddHighHob) {
> > -        DEBUG ((
> > -          DEBUG_INFO,
> > -          "%a: Reserved: Base=0x%Lx Length=0x%Lx\n",
> > -          __FUNCTION__,
> > -          E820Entry.BaseAddr,
> > -          E820Entry.Length
> > -          ));
> > -        BuildResourceDescriptorHob (
> > -          EFI_RESOURCE_MEMORY_RESERVED,
> > -          0,
> > -          E820Entry.BaseAddr,
> > -          E820Entry.Length
> > -          );
> > -      }
> > -    }
> > -  }
> > -
> > -  return EFI_SUCCESS;
> > -}
> > -
> >  typedef VOID (*E820_SCAN_CALLBACK) (
> >    EFI_E820_ENTRY64       *E820Entry,
> >    EFI_HOB_PLATFORM_INFO  *PlatformInfoHob
> > @@ -304,6 +167,52 @@ PlatformGetLowMemoryCB (
> >    }
> >  }
> >
> > +/**
> > +  Create HOBs for reservations and RAM (except low memory).
> > +**/
> > +STATIC VOID
> > +PlatformAddHobCB (
> > +  IN     EFI_E820_ENTRY64       *E820Entry,
> > +  IN OUT EFI_HOB_PLATFORM_INFO  *PlatformInfoHob
> > +  )
> > +{
> > +  UINT64  Base, End;
> > +
> > +  Base = E820Entry->BaseAddr;
> > +  End  = E820Entry->BaseAddr + E820Entry->Length;
> > +
> > +  switch (E820Entry->Type) {
> > +    case EfiAcpiAddressRangeMemory:
> > +      if (Base >= BASE_4GB) {
> > +        //
> > +        // Round up the start address, and round down the end address.
> > +        //
> > +        Base = ALIGN_VALUE (Base, (UINT64)EFI_PAGE_SIZE);
> > +        End  = End & ~(UINT64)EFI_PAGE_MASK;
> > +        if (Base < End) {
> > +          DEBUG ((DEBUG_INFO, "%a: HighMemory [0x%Lx, 0x%Lx)\n", __FUNCTION__, Base, End-1));
>
> (1) Hehe, this is a bit funny: we now have *both* the round closing
> parenthesies ")" in the debug message, for the interval, *and* (End-1)
> as the argument! :)
>
> We need exactly one of those. Either-or. :) If the argument is exclusive
> ("End"), then the interval should be closed with ")". If the arg is
> inclusive ("End-1"), then we need a bracket "]".
>
> > +          PlatformAddMemoryRangeHob (Base, End);
> > +        }
> > +      }
> > +
>
> (2) Still not sure if this empty line is intentional (it may be, you
> didn't answer it under the v2 review AFAICT).
>
> > +      break;
> > +    case EfiAcpiAddressRangeReserved:
> > +      BuildResourceDescriptorHob (EFI_RESOURCE_MEMORY_RESERVED, 0, Base, End);
> > +      DEBUG ((DEBUG_INFO, "%a: Reserved [0x%Lx, 0x%Lx)\n", __FUNCTION__, Base, End-1));
>
> (3) Same comment as (1) -- please pick either End-1 as arg, with "]", or
> ")" as interval closing character, with End as arg.
>
> > +      break;
> > +    default:
> > +      DEBUG ((
> > +        DEBUG_WARN,
> > +        "%a: Type %u [0x%Lx, 0x%Lx) (NOT HANDLED)\n",
> > +        __FUNCTION__,
> > +        E820Entry->Type,
> > +        Base,
> > +        End-1
> > +        ));
> > +      break;
> > +  }
>
> (4) Same as (1).
>
> > +}
> > +
> >  /**
> >    Iterate over the entries in QEMU's fw_cfg E820 RAM map, call the
> >    passed callback for each entry.
> > @@ -1049,7 +958,7 @@ PlatformQemuInitializeRam (
> >      // entries. Otherwise, create a single memory HOB with the flat >=4GB
> >      // memory size read from the CMOS.
> >      //
> > -    Status = PlatformScanOrAdd64BitE820Ram (TRUE, NULL, NULL);
> > +    Status = PlatformScanE820 (PlatformAddHobCB, PlatformInfoHob);
> >      if (EFI_ERROR (Status)) {
> >        UpperMemorySize = PlatformGetSystemMemorySizeAbove4gb ();
> >        if (UpperMemorySize != 0) {
>
> Update as you see fit, either way:
>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
>

Thanks Laszlo - I'll fix up the above locally.