Commit Graph

5 Commits

Author SHA1 Message Date
Anthony PERARD 29280c7084 OvmfPkg/XenResetVector: Silent a warning from nasm
To avoid nasm generating a warning, replace the macro by the value
expected to be stored in eax.
  Ia32/XenPVHMain.asm:76: warning: dword data exceeds bounds

Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20210412133003.146438-2-anthony.perard@citrix.com>
2021-04-13 11:54:58 +00:00
Anthony PERARD f198e254f7 OvmfPkg/XenResetVector: Allow jumpstart from either hvmloader or PVH
This patch allows the ResetVector to be run indenpendently from build
time addresses.

The goal of the patch is to avoid having to create RAM just below 4G
when creating a Xen PVH guest while being compatible with the way
hvmloader currently load OVMF, just below 4G.

Only the new PVH entry point will do the calculation.

The ResetVector will figure out its current running address by creating
a temporary stack, make a call and calculate the difference between the
build time address and the address at run time.

This patch copies and make the necessary modification to some other asm
files:
- copy of UefiCpuPkg/.../Flat32ToFlat64.asm:
  Allow Transition32FlatTo64Flat to be run from anywhere in memory
- copy of UefiCpuPkg/../SearchForBfvBase.asm:
  Add a extra parameter to indicate where to start the search for the
  boot firmware volume.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20190813113119.14804-9-anthony.perard@citrix.com>
2019-08-21 18:03:49 +02:00
Anthony PERARD 93314ae597 OvmfPkg/XenResetVector: Saving start of day pointer for PVH guests
As described in the Xen PVH documentation [1], "ebx: contains the
physical memory address where the loader has placed the boot start info
structure". To have this pointer saved to be able to use it later in the
PEI phase, we allocate some space in the MEMFD for it. We use 'XPVH' as
a signature (for "Xen PVH").

[1] https://xenbits.xenproject.org/docs/unstable/misc/pvh.html

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20190813113119.14804-8-anthony.perard@citrix.com>
2019-08-21 18:03:49 +02:00
Anthony PERARD a8c791c15b OvmfPkg/XenResetVector: Add new entry point for Xen PVH
Add a new entry point for Xen PVH that enter directly in 32bits.

Information on the expected state of the machine when this entry point
is used can be found at:
https://xenbits.xenproject.org/docs/unstable/misc/pvh.html

Also, compare to the original file [1], the two `nop' of the "resetVector"
entry point are removed. There were introduced by 8332983e2e
("UefiCpuPkg: Replace the un-necessary WBINVD instruction at the reset
vector with two NOPs in VTF0.", 2011-08-04), but don't seems to be
useful. This is the entry point used by HVM guest (hvmloader).

[1] UefiCpuPkg/ResetVector/Vtf0/Ia16/ResetVectorVtf0.asm

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20190813113119.14804-7-anthony.perard@citrix.com>
2019-08-21 18:03:49 +02:00
Anthony PERARD c05de360ec OvmfPkg: Introduce XenResetVector
Introduce XenResetVector, a copy of OvmfPkg/ResetVector, with one
changes:
  - SEC_DEFAULT_CR0: enable cache (bit 30 or CD set to 0)

Xen copies the OVMF code to RAM, there is no need to disable cache.

This new module will later be modified to add a new entry point, more
detail in a following commit "OvmfPkg/XenResetVector: Add new entry point
for Xen PVH"

Value FILE_GUID of XenResetVector have not changed compare to ResetVector
because it is a special value (gEfiFirmwareVolumeTopFileGuid).

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20190813113119.14804-4-anthony.perard@citrix.com>
2019-08-21 18:03:49 +02:00