Commit 09719a01b1 (OvmfPkg/QemuFwCfgLib: Implement SEV internal function
for Dxe phase) uses IOMMU protocol to allocate and free FW_CFG_DMA_ACCESS
buffer when SEV is active. During initial commits we made assumption that
IOMMU.AllocateBuffer() will provide PlainTextAddress (i.e C-bit cleared).
This assumption was wrong, the AllocateBuffer() protocol member is not
expected to produce a buffer that is immediatly usable, and client is
required to call Map() uncondtionally with BusMasterCommonBuffer[64] to
get a mapping which is accessable by both host and device.
The patch refactors code a bit and add the support to Map()
FW_CFG_DMA_ACCESS buffer using BusMasterCommonBuffer operation after
allocation and Unamp() before free.
The complete discussion about this and recommendation from Laszlo can be
found here [1]
[1] https://lists.01.org/pipermail/edk2-devel/2017-July/012652.html
Suggested-by: Laszlo Ersek <lersek@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
[lersek@redhat.com: convert pointers to UINTN before converting to UINT64]
[lersek@redhat.com: fix argument indentation in multi-line function call]
[lersek@redhat.com: explicitly compare pointers to NULL]
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
When SEV is enabled, the DMA must be performed on unencrypted pages.
So when get asked to perfom FWCFG DMA read or write, we allocate a
intermediate (bounce buffer) unencrypted buffer and use this buffer
for DMA read or write.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Current QemuFwCfgLib.inf is used in both Pei and Dxe phases. Add Pei
and Dxe inf file to provide a seperate QemuFwCfgLib instances for Pei
and Dxe phases.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Brijesh Singh