mirror of https://github.com/acidanthera/audk.git
2520182122
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> |
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| README | ||
README
This is an *experimental* port of OVMF for the QEMU microvm machine type. microvm background info ----------------------- microvm is designed for modern, virtio-based workloads. Most legacy lpc/isa devices like pit and pic can be turned off. virtio-mmio (i.e. '-device virtio-{blk,net,scsi,...}-device') is used for storage/network/etc. Optional pcie support is available and any pcie device supported by QEMU can be plugged in (including virtio-pci if you prefer that over virtio-mmio). https://qemu.readthedocs.io/en/latest/system/i386/microvm.html https://www.kraxel.org/blog/2020/10/qemu-microvm-acpi/ design issues ------------- Not fully clear yet how to do hardware detection best. Right now using device tree to find virtio-mmio devices and pcie host bridge, can reuse existing ArmVirtPkg code that way. Needs patched QEMU. features -------- [working] serial console [working] direct kernel boot [working] virtio-mmio support [in progress] pcie support known limitations ----------------- * rtc=on is required for now. * can't use separate code/vars (actually an microvm limitation, there is no pflash support). * transitional virtio-pci devices do not work. microvm doesn't support ioports on pcie, and ovmf doesn't initialize pcie devices with ioports if there is no address space for them (even though pcie devices are required to be functional without ioports). usage ----- qemu-system-x86_64 \ -nographic \ -machine microvm,acpi=on,pit=off,pic=off,rtc=on \ -bios /path/to/MICROVM.fd \ [ ... more args here ... ]