Instead of relying on raising the TPL to protect the critical sections
that manipulate the global bitmask that keeps track of bounce buffer
allocations, use compare-and-exchange to manage the global variable, and
tweak the logic to line up with that.
Given that IoMmuDxe implements a singleton protocol that is shared
between multiple drivers, and considering the elaborate and confusing
requirements in the UEFP spec regarding TPL levels at which protocol
methods may be invoked, not relying on TPL levels at all is a more
robust approach in this case.
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2211060
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Pedro Falcato <pedro.falcato@gmail.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4171
IoMmuDxe once was designed to support DMA operation when SEV is enabled.
After TDX is enabled in IoMmuDxe, some files' name in IoMmuDxe need to
be more general. So this patch rename:
AmdSevIoMmu.h -> CcIoMmu.h
AmdSevIoMmu.c -> CcIoMmu.c
Accordingly there are some udates in IoMmuDxe.c and IoMmuDxe.inf.
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4171
A typical QEMU fw_cfg read bytes with IOMMU for td guest is that:
(QemuFwCfgReadBytes@QemuFwCfgLib.c is the example)
1) Allocate DMA Access buffer
2) Map actual data buffer
3) start the transfer and wait for the transfer to complete
4) Free DMA Access buffer
5) Un-map actual data buffer
In step 1/2, Private memories are allocated, converted to shared memories.
In Step 4/5 the shared memories are converted to private memories and
accepted again. The final step is to free the pages.
This is time-consuming and impacts td guest's boot perf (both direct boot
and grub boot) badly.
In a typical grub boot, there are about 5000 calls of page allocation and
private/share conversion. Most of page size is less than 32KB.
This patch allocates a memory region and initializes it into pieces of
memory with different sizes. A piece of such memory consists of 2 parts:
the first page is of private memory, and the other pages are shared
memory. This is to meet the layout of common buffer.
When allocating bounce buffer in IoMmuMap(), IoMmuAllocateBounceBuffer()
is called to allocate the buffer. Accordingly when freeing bounce buffer
in IoMmuUnmapWorker(), IoMmuFreeBounceBuffer() is called to free the
bounce buffer. CommonBuffer is allocated by IoMmuAllocateCommonBuffer
and accordingly freed by IoMmuFreeCommonBuffer.
This feature is tested in Intel TDX pre-production platform. It saves up
to hundreds of ms in a grub boot.
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
The IOMMU protocol driver provides capabilities to set a DMA access
attribute and methods to allocate, free, map and unmap the DMA memory
for the PCI Bus devices.
The current IoMmuDxe driver supports DMA operations inside SEV guest.
To support DMA operation in TDX guest,
CC_GUEST_IS_XXX (PcdConfidentialComputingGuestAttr) is used to determine
if it is SEV guest or TDX guest.
Due to security reasons all DMA operations inside the SEV/TDX guest must
be performed on shared pages. The IOMMU protocol driver for the SEV/TDX
guest uses a bounce buffer to map guest DMA buffer to shared pages in
order to provide the support for DMA operations inside SEV/TDX guest.
The call of SEV or TDX specific function to set/clear EncMask/SharedBit
is determined by CC_GUEST_IS_XXX (PcdConfidentialComputingGuestAttr).
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
The header file declares the AmdSevInstallIoMmuProtocol() function, which
is implemented in "AmdSevIoMmu.c" and called from "IoMmuDxe.c".
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Suggested-by: Michael Kinney <michael.d.kinney@intel.com>
Ref: http://mid.mail-archive.com/E92EE9817A31E24EB0585FDF735412F56327F7D3@ORSMSX113.amr.corp.intel.com
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
The following library classes are not used by this module, so remove them
from the INF file's [LibraryClasses] section:
- DxeServicesTableLib
- UefiLib
The following library classes are used by this module, so add them to the
INF file's [LibraryClasses] section:
- BaseMemoryLib (e.g. via CopyMem())
- MemoryAllocationLib (e.g. via AllocatePool())
Sort the list of library classes (in both "IoMmuDxe.inf" and
"AmdSevIoMmu.h").
Remove all non-local #include directives from "IoMmuDxe.c"; both C files
of this module include "AmdSevIoMmu.h", and "AmdSevIoMmu.h" includes all
non-local headers already.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
The IOMMU protocol driver provides capabilities to set a DMA access
attribute and methods to allocate, free, map and unmap the DMA memory
for the PCI Bus devices.
Due to security reasons all DMA operations inside the SEV guest must
be performed on shared (i.e unencrypted) pages. The IOMMU protocol
driver for the SEV guest uses a bounce buffer to map guest DMA buffer
to shared pages inorder to provide the support for DMA operations inside
SEV guest.
IoMmuDxe driver looks for SEV capabilities, if present then it installs
the real IOMMU protocol otherwise it installs placeholder protocol.
Currently, PciHostBridgeDxe and QemuFWCfgLib need to know the existance
of IOMMU protocol. The modules needing to know the existance of IOMMU
support should add
gEdkiiIoMmuProtocolGuid OR gIoMmuAbsentProtocolGuid
in their depex to ensure that platform IOMMU detection has been performed.
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Leo Duran <leo.duran@amd.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Suggested-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>
Ard Biesheuvel
Min M Xu
Michael D Kinney
Laszlo Ersek
Brijesh Singh