TESTING-ONLY: Apic mmio fix4 #5618
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Future changes will make use of CpuPageTableLib to handle splitting page table mappings during SEC phase. While it's not strictly required by hardware, CpuPageTableLib relies on non-leaf PTEs never having the encryption bit set, so go ahead change the page table setup code to satisfy this expectation. Suggested-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Erdem Aktas <erdemaktas@google.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Min Xu <min.m.xu@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Michael Roth <michael.roth@amd.com>
For the most part, OVMF will clear the encryption bit for MMIO regions, but there is currently one known exception during SEC when the APIC base address is accessed via MMIO with the encryption bit set for SEV-ES/SEV-SNP guests. In the case of SEV-SNP, this requires special handling on the hypervisor side which may not be available in the future[1], so make the necessary changes in the SEC-configured page table to clear the encryption bit for 4K region containing the APIC base address. [1] https://lore.kernel.org/lkml/20240208002420.34mvemnzrwwsaesw@amd.com/#t Suggested-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Erdem Aktas <erdemaktas@google.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Min Xu <min.m.xu@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Jianyong Wu <jianyong.wu@arm.com> Cc: Anatol Belski <anbelski@linux.microsoft.com> Signed-off-by: Michael Roth <michael.roth@amd.com>
The current #VC handler guards against MMIO to addresses that are mapped with the encryption bit set, but has an special exception for MMIO accesses to the APIC base address so allow for early access during SEC. Now that the SEC page table has the encryption bit cleared for the APIC base address range, there is no longer any need for this special handling. Go ahead and remove it. Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Erdem Aktas <erdemaktas@google.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Min Xu <min.m.xu@intel.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Michael Roth <michael.roth@amd.com>
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