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2024-10-28x86/sev: Convert shared memory back to private on kexecAshish Kalra
SNP guests allocate shared buffers to perform I/O. It is done by allocating pages normally from the buddy allocator and converting them to shared with set_memory_decrypted(). The second, kexec-ed, kernel has no idea what memory is converted this way. It only sees E820_TYPE_RAM. Accessing shared memory via private mapping will cause unrecoverable RMP page-faults. On kexec, walk direct mapping and convert all shared memory back to private. It makes all RAM private again and second kernel may use it normally. Additionally, for SNP guests, convert all bss decrypted section pages back to private. The conversion occurs in two steps: stopping new conversions and unsharing all memory. In the case of normal kexec, the stopping of conversions takes place while scheduling is still functioning. This allows for waiting until any ongoing conversions are finished. The second step is carried out when all CPUs except one are inactive and interrupts are disabled. This prevents any conflicts with code that may access shared memory. Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/05a8c15fb665dbb062b04a8cb3d592a63f235937.1722520012.git.ashish.kalra@amd.com
2024-10-16virt: sev-guest: Consolidate SNP guest messaging parameters to a structNikunj A Dadhania
Add a snp_guest_req structure to eliminate the need to pass a long list of parameters. This structure will be used to call the SNP Guest message request API, simplifying the function arguments. Update the snp_issue_guest_request() prototype to include the new guest request structure. Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20241009092850.197575-5-nikunj@amd.com
2024-10-16x86/sev: Cache the secrets page addressNikunj A Dadhania
Instead of calling get_secrets_page(), which parses the CC blob every time to get the secrets page physical address (secrets_pa), save the secrets page physical address during snp_init() from the CC blob. Since get_secrets_page() is no longer used, remove the function. Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20241009092850.197575-4-nikunj@amd.com
2024-10-15x86/virt: Move SEV-specific parsing into arch/x86/virt/svmPavan Kumar Paluri
Move SEV-specific kernel command line option parsing support from arch/x86/coco/sev/core.c to arch/x86/virt/svm/cmdline.c so that both host and guest related SEV command line options can be supported. No functional changes intended. Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20241014130948.1476946-2-papaluri@amd.com
2024-07-30x86/sev: Fix __reserved field in sev_configPavan Kumar Paluri
sev_config currently has debug, ghcbs_initialized, and use_cas fields. However, __reserved count has not been updated. Fix this. Fixes: 34ff65901735 ("x86/sev: Use kernel provided SVSM Calling Areas") Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20240729180808.366587-1-papaluri@amd.com
2024-07-11x86/sev: Move SEV compilation unitsBorislav Petkov (AMD)
A long time ago it was agreed upon that the coco stuff needs to go where it belongs: https://lore.kernel.org/all/Yg5nh1RknPRwIrb8@zn.tnic and not keep it in arch/x86/kernel. TDX did that and SEV can't find time to do so. So lemme do it. If people have trouble converting their ongoing featuritis patches, ask me for a sed script. No functional changes. Move the instrumentation exclusion bits too, as helpfully caught and reported by the 0day folks. Closes: https://lore.kernel.org/oe-kbuild-all/202406220748.hG3qlmDx-lkp@intel.com Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-lkp/202407091342.46d7dbb-oliver.sang@intel.com Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Nikunj A Dadhania <nikunj@amd.com> Reviewed-by: Ashish Kalra <ashish.kalra@amd.com> Tested-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/r/20240619093014.17962-1-bp@kernel.org