linux-dev/arch/x86/kernel/sev.c, branch linus/master

x86/sev: Fix address space sparse warning

2022-05-02T15:34:29Z

Fix: arch/x86/kernel/sev.c:605:16: warning: incorrect type in assignment (different address spaces) arch/x86/kernel/sev.c:605:16: expected struct snp_secrets_page_layout *layout arch/x86/kernel/sev.c:605:16: got void [noderef] __iomem *[assigned] mem Reported-by: kernel test robot Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/202205022233.XgNDR7WR-lkp@intel.com

x86/sev: Get the AP jump table address from secrets page

2022-04-27T11:31:38Z

The GHCB specification section 2.7 states that when SEV-SNP is enabled, a guest should not rely on the hypervisor to provide the address of the AP jump table. Instead, if a guest BIOS wants to provide an AP jump table, it should record the address in the SNP secrets page so the guest operating system can obtain it directly from there. Fix this on the guest kernel side by having SNP guests use the AP jump table address published in the secrets page rather than issuing a GHCB request to get it. [ mroth: - Improve error handling when ioremap()/memremap() return NULL - Don't mix function calls with declarations - Add missing __init - Tweak commit message ] Fixes: 0afb6b660a6b ("x86/sev: Use SEV-SNP AP creation to start secondary CPUs") Signed-off-by: Brijesh Singh Signed-off-by: Michael Roth Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220422135624.114172-3-michael.roth@amd.com

x86/sev: Add missing __init annotations to SEV init routines

2022-04-27T11:31:36Z

Currently, get_secrets_page() is only reachable from the following call chain: __init snp_init_platform_device(): get_secrets_page() so mark it as __init as well. This is also needed since it calls early_memremap(), which is also an __init routine. Similarly, get_jump_table_addr() is only reachable from the following call chain: __init setup_real_mode(): sme_sev_setup_real_mode(): sev_es_setup_ap_jump_table(): get_jump_table_addr() so mark get_jump_table_addr() and everything up that call chain as __init as well. This is also needed since future patches will add a call to get_secrets_page(), which needs to be __init due to the reasons stated above. Suggested-by: Borislav Petkov Signed-off-by: Michael Roth Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220422135624.114172-2-michael.roth@amd.com

virt: sevguest: Change driver name to reflect generic SEV support

2022-04-21T09:48:24Z

During patch review, it was decided the SNP guest driver name should not be SEV-SNP specific, but should be generic for use with anything SEV. However, this feedback was missed and the driver name, and many of the driver functions and structures, are SEV-SNP name specific. Rename the driver to "sev-guest" (to match the misc device that is created) and update some of the function and structure names, too. While in the file, adjust the one pr_err() message to be a dev_err() message so that the message, if issued, uses the driver name. Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/307710bb5515c9088a19fd0b930268c7300479b2.1650464054.git.thomas.lendacky@amd.com

x86/sev-es: Replace open-coded hlt-loop with sev_es_terminate()

2022-04-08T08:57:35Z

Replace the halt loop in handle_vc_boot_ghcb() with an sev_es_terminate(). The HLT gives the system no indication the guest is unhappy. The termination request will signal there was an error during VC handling during boot. [ bp: Update it to pass the reason set too. ] Signed-off-by: Peter Gonda Signed-off-by: Borislav Petkov Reviewed-by: Joerg Roedel Link: https://lore.kernel.org/r/20220317211913.1397427-1-pgonda@google.com

x86/sev: Register SEV-SNP guest request platform device

2022-04-07T14:47:12Z

Version 2 of the GHCB specification provides a Non Automatic Exit (NAE) event type that can be used by the SEV-SNP guest to communicate with the PSP without risk from a malicious hypervisor who wishes to read, alter, drop or replay the messages sent. SNP_LAUNCH_UPDATE can insert two special pages into the guest’s memory: the secrets page and the CPUID page. The PSP firmware populates the contents of the secrets page. The secrets page contains encryption keys used by the guest to interact with the firmware. Because the secrets page is encrypted with the guest’s memory encryption key, the hypervisor cannot read the keys. See SEV-SNP firmware spec for further details on the secrets page format. Create a platform device that the SEV-SNP guest driver can bind to get the platform resources such as encryption key and message id to use to communicate with the PSP. The SEV-SNP guest driver provides a userspace interface to get the attestation report, key derivation, extended attestation report etc. Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-43-brijesh.singh@amd.com

x86/sev: Provide support for SNP guest request NAEs

2022-04-07T14:47:12Z

Version 2 of GHCB specification provides SNP_GUEST_REQUEST and SNP_EXT_GUEST_REQUEST NAE that can be used by the SNP guest to communicate with the PSP. While at it, add a snp_issue_guest_request() helper that will be used by driver or other subsystem to issue the request to PSP. See SEV-SNP firmware and GHCB spec for more details. Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-42-brijesh.singh@amd.com

x86/sev: Add a sev= cmdline option

2022-04-07T14:47:12Z

For debugging purposes it is very useful to have a way to see the full contents of the SNP CPUID table provided to a guest. Add an sev=debug kernel command-line option to do so. Also introduce some infrastructure so that additional options can be specified via sev=option1[,option2] over time in a consistent manner. [ bp: Massage, simplify string parsing. ] Suggested-by: Borislav Petkov Signed-off-by: Michael Roth Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-41-brijesh.singh@amd.com

x86/sev: Use firmware-validated CPUID for SEV-SNP guests

2022-04-07T14:47:12Z

SEV-SNP guests will be provided the location of special 'secrets' and 'CPUID' pages via the Confidential Computing blob. This blob is provided to the run-time kernel either through a boot_params field that was initialized by the boot/compressed kernel, or via a setup_data structure as defined by the Linux Boot Protocol. Locate the Confidential Computing blob from these sources and, if found, use the provided CPUID page/table address to create a copy that the run-time kernel will use when servicing CPUID instructions via a #VC handler. Signed-off-by: Michael Roth Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-40-brijesh.singh@amd.com

x86/sev: Add SEV-SNP feature detection/setup

2022-04-07T14:47:11Z

Initial/preliminary detection of SEV-SNP is done via the Confidential Computing blob. Check for it prior to the normal SEV/SME feature initialization, and add some sanity checks to confirm it agrees with SEV-SNP CPUID/MSR bits. Signed-off-by: Michael Roth Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-39-brijesh.singh@amd.com