[PATCH v2 0/2] x86/sev: Fix RMPOPT enablement on non-RMPOPT configs

[Ashish Kalra <Ashish.Kalra@amd.com>]

From: Ashish Kalra <ashish.kalra@amd.com>

Two fixes for the RMPOPT series, both for configurations where the
RMPOPT CPUID bit is advertised but RMPOPT is not actually usable:

Patch 1 clears X86_FEATURE_RMPOPT when the platform advertises segmented
RMP but the firmware has it disabled (contiguous RMP) - otherwise the
RMPOPT initcall programs RMPOPT_BASE and issues RMPOPT, which #GP.

Patch 2 gates rmpopt_init() on X86_FEATURE_SEV_SNP as well, so the RMPOPT
workqueue setup and the "optimizations enabled" message only happen on an
SNP host - e.g. not when SNP is disabled in the BIOS.

v2:
 - Patch 1: expand the commit message to spell out the CPUID-advertise vs
   firmware-enable distinction and how the configuration arises; drop the
   trailing sentence; add Tom's Reviewed-by.
 - Patch 2: rather than moving the announcement to snp_enable_rmpopt(),
   gate rmpopt_init() on X86_FEATURE_SEV_SNP and keep the message there
   (Tom).

Ashish Kalra (2):
  x86/sev: Clear RMPOPT when segmented RMP is disabled by firmware
  x86/sev: Only announce RMPOPT optimizations when SNP is enabled

 arch/x86/virt/svm/sev.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)


base-commit: 250ee734115bca1c1f7a38d838909aa83cce87ae
-- 
2.43.0