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| author | Nikunj A Dadhania <nikunj@amd.com> | 2026-03-18 10:56:54 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-02 14:23:20 +0300 |
| commit | 4cce3cd5ed79fc604541fc3bbddccd63b0ef60a1 (patch) | |
| tree | 12db6d1483f24b3300b011873ce03413d3dc0ac0 /arch | |
| parent | a6e14114684d2324e5401617d6d01acb4a4e0e22 (diff) | |
| download | linux-4cce3cd5ed79fc604541fc3bbddccd63b0ef60a1.tar.xz | |
x86/fred: Fix early boot failures on SEV-ES/SNP guests
commit 3645eb7e3915990a149460c151a00894cb586253 upstream.
FRED-enabled SEV-(ES,SNP) guests fail to boot due to the following issues
in the early boot sequence:
* FRED does not have a #VC exception handler in the dispatch logic
* Early FRED #VC exceptions attempt to use uninitialized per-CPU GHCBs
instead of boot_ghcb
Add X86_TRAP_VC case to fred_hwexc() with a new exc_vmm_communication()
function that provides the unified entry point FRED requires, dispatching
to existing user/kernel handlers based on privilege level. The function is
already declared via DECLARE_IDTENTRY_VC().
Fix early GHCB access by falling back to boot_ghcb in
__sev_{get,put}_ghcb() when per-CPU GHCBs are not yet initialized.
Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code")
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>
Cc: <stable@kernel.org> # 6.12+
Link: https://patch.msgid.link/20260318075654.1792916-4-nikunj@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/coco/sev/noinstr.c | 6 | ||||
| -rw-r--r-- | arch/x86/entry/entry_fred.c | 14 |
2 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/coco/sev/noinstr.c b/arch/x86/coco/sev/noinstr.c index b527eafb6312..422ce72f51d5 100644 --- a/arch/x86/coco/sev/noinstr.c +++ b/arch/x86/coco/sev/noinstr.c @@ -120,6 +120,9 @@ noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state) WARN_ON(!irqs_disabled()); + if (!sev_cfg.ghcbs_initialized) + return boot_ghcb; + data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; @@ -163,6 +166,9 @@ noinstr void __sev_put_ghcb(struct ghcb_state *state) WARN_ON(!irqs_disabled()); + if (!sev_cfg.ghcbs_initialized) + return; + data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; diff --git a/arch/x86/entry/entry_fred.c b/arch/x86/entry/entry_fred.c index 563e439b743f..9f50f0c1c00f 100644 --- a/arch/x86/entry/entry_fred.c +++ b/arch/x86/entry/entry_fred.c @@ -176,6 +176,16 @@ static noinstr void fred_extint(struct pt_regs *regs) } } +#ifdef CONFIG_AMD_MEM_ENCRYPT +noinstr void exc_vmm_communication(struct pt_regs *regs, unsigned long error_code) +{ + if (user_mode(regs)) + return user_exc_vmm_communication(regs, error_code); + else + return kernel_exc_vmm_communication(regs, error_code); +} +#endif + static noinstr void fred_hwexc(struct pt_regs *regs, unsigned long error_code) { /* Optimize for #PF. That's the only exception which matters performance wise */ @@ -206,6 +216,10 @@ static noinstr void fred_hwexc(struct pt_regs *regs, unsigned long error_code) #ifdef CONFIG_X86_CET case X86_TRAP_CP: return exc_control_protection(regs, error_code); #endif +#ifdef CONFIG_AMD_MEM_ENCRYPT + case X86_TRAP_VC: return exc_vmm_communication(regs, error_code); +#endif + default: return fred_bad_type(regs, error_code); } |