kernel.git/arch/x86/kernel/sev.c, branch linux-5.13.y

x86/sev: Use "SEV: " prefix for messages from sev.c

2021-07-14T15:06:48Z

[ Upstream commit 8d9d46bbf3b6b7ff8edcac33603ab45c29e0e07f ] The source file has been renamed froms sev-es.c to sev.c, but the messages are still prefixed with "SEV-ES: ". Change that to "SEV: " to make it consistent. Fixes: e759959fe3b8 ("x86/sev-es: Rename sev-es.{ch} to sev.{ch}") Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210622144825.27588-4-joro@8bytes.org Signed-off-by: Sasha Levin

x86/sev: Split up runtime #VC handler for correct state tracking

2021-07-14T15:06:48Z

[ Upstream commit be1a5408868af341f61f93c191b5e346ee88c82a ] Split up the #VC handler code into a from-user and a from-kernel part. This allows clean and correct state tracking, as the #VC handler needs to enter NMI-state when raised from kernel mode and plain IRQ state when raised from user-mode. Fixes: 62441a1fb532 ("x86/sev-es: Correctly track IRQ states in runtime #VC handler") Suggested-by: Peter Zijlstra Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20210618115409.22735-3-joro@8bytes.org Signed-off-by: Sasha Levin

x86/sev: Make sure IRQs are disabled while GHCB is active

2021-07-14T15:06:47Z

[ Upstream commit d187f217335dba2b49fc9002aab2004e04acddee ] The #VC handler only cares about IRQs being disabled while the GHCB is active, as it must not be interrupted by something which could cause another #VC while it holds the GHCB (NMI is the exception for which the backup GHCB exits). Make sure nothing interrupts the code path while the GHCB is active by making sure that callers of __sev_{get,put}_ghcb() have disabled interrupts upfront. [ bp: Massage commit message. ] Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20210618115409.22735-2-joro@8bytes.org Signed-off-by: Sasha Levin

x86/sev-es: Use __put_user()/__get_user() for data accesses

2021-05-19T16:45:37Z

The put_user() and get_user() functions do checks on the address which is passed to them. They check whether the address is actually a user-space address and whether its fine to access it. They also call might_fault() to indicate that they could fault and possibly sleep. All of these checks are neither wanted nor needed in the #VC exception handler, which can be invoked from almost any context and also for MMIO instructions from kernel space on kernel memory. All the #VC handler wants to know is whether a fault happened when the access was tried. This is provided by __put_user()/__get_user(), which just do the access no matter what. Also add comments explaining why __get_user() and __put_user() are the best choice here and why it is safe to use them in this context. Also explain why copy_to/from_user can't be used. In addition, also revert commit 7024f60d6552 ("x86/sev-es: Handle string port IO to kernel memory properly") because using __get_user()/__put_user() fixes the same problem while the above commit introduced several problems: 1) It uses access_ok() which is only allowed in task context. 2) It uses memcpy() which has no fault handling at all and is thus unsafe to use here. [ bp: Fix up commit ID of the reverted commit above. ] Fixes: f980f9c31a92 ("x86/sev-es: Compile early handler code into kernel image") Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org # v5.10+ Link: https://lkml.kernel.org/r/20210519135251.30093-4-joro@8bytes.org

x86/sev-es: Forward page-faults which happen during emulation

2021-05-19T15:13:04Z

When emulating guest instructions for MMIO or IOIO accesses, the #VC handler might get a page-fault and will not be able to complete. Forward the page-fault in this case to the correct handler instead of killing the machine. Fixes: 0786138c78e7 ("x86/sev-es: Add a Runtime #VC Exception Handler") Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org # v5.10+ Link: https://lkml.kernel.org/r/20210519135251.30093-3-joro@8bytes.org

x86/sev-es: Don't return NULL from sev_es_get_ghcb()

2021-05-19T15:05:13Z

sev_es_get_ghcb() is called from several places but only one of them checks the return value. The reaction to returning NULL is always the same: calling panic() and kill the machine. Instead of adding checks to all call sites, move the panic() into the function itself so that it will no longer return NULL. Fixes: 0786138c78e7 ("x86/sev-es: Add a Runtime #VC Exception Handler") Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org # v5.10+ Link: https://lkml.kernel.org/r/20210519135251.30093-2-joro@8bytes.org

x86/sev-es: Invalidate the GHCB after completing VMGEXIT

2021-05-18T05:06:29Z

Since the VMGEXIT instruction can be issued from userspace, invalidate the GHCB after performing VMGEXIT processing in the kernel. Invalidation is only required after userspace is available, so call vc_ghcb_invalidate() from sev_es_put_ghcb(). Update vc_ghcb_invalidate() to additionally clear the GHCB exit code so that it is always presented as 0 when VMGEXIT has been issued by anything else besides the kernel. Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/5a8130462e4f0057ee1184509cd056eedd78742b.1621273353.git.thomas.lendacky@amd.com

x86/sev-es: Move sev_es_put_ghcb() in prep for follow on patch

2021-05-18T04:49:37Z

Move the location of sev_es_put_ghcb() in preparation for an update to it in a follow-on patch. This will better highlight the changes being made to the function. No functional change. Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/8c07662ec17d3d82e5c53841a1d9e766d3bdbab6.1621273353.git.thomas.lendacky@amd.com

x86/sev-es: Rename sev-es.{ch} to sev.{ch}

2021-05-10T05:40:27Z

SEV-SNP builds upon the SEV-ES functionality while adding new hardware protection. Version 2 of the GHCB specification adds new NAE events that are SEV-SNP specific. Rename the sev-es.{ch} to sev.{ch} so that all SEV* functionality can be consolidated in one place. Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Acked-by: Joerg Roedel Link: https://lkml.kernel.org/r/20210427111636.1207-2-brijesh.singh@amd.com