Nikunj A Dadhania 70cad63b3b x86/fred: Fix early boot failures on SEV-ES/SNP guests ...

[ Upstream commit 3645eb7e39 ]

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: 14619d912b ("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
[ applied GHCB early-return changes to core.c instead of noinstr.c ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2026-04-11 14:24:52 +02:00

..

sev

x86/fred: Fix early boot failures on SEV-ES/SNP guests

2026-04-11 14:24:52 +02:00

tdx

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core.c

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Makefile

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