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amd64: properly recalculate mitigations knobs after resume

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Revision r333125 AKA 986c4ca387 forced clear cpu_stdext_feature3
on suspend, since at that time microcode update was not reloaded
early on resume. Then, revision 050f5a8405 started re-reading
cpu_stdext_feature3 again. Since modern CPUs do not require mitigations
from the Skylake era, this went unnoticed for some time.

Keep zeroing cpu_stdext_feature3 on suspend, but re-read it in more
controlled way on resume after microcode is reloaded, and recalculate
active workarounds based on actual microcode capabilities.

Reported and tested by:	romain
Reviewed by:	emaste, markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D39146
This commit is contained in:
Konstantin Belousov 2023-03-17 15:02:03 +02:00
parent 9ee6278b78
commit 02904a06c7
2 changed files with 15 additions and 1 deletions
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14
sys/amd64/acpica/acpi_wakeup.c
View File

@ -288,6 +288,20 @@ acpi_wakeup_machdep(struct acpi_softc *sc, int state, int sleep_result,
if (!CPU_EMPTY(&suspcpus))
resume_cpus(suspcpus);
#endif
/*
* Re-read cpu_stdext_feature3, which was zeroed-out
* in acpi_sleep_machdep, after the microcode was
* reloaded. Then recalculate the active mitigations
* knobs that depend on the microcode and
* cpu_stdext_feature3.
*/
identify_cpu_ext_features();
hw_ibrs_recalculate(true);
hw_ssb_recalculate(true);
amd64_syscall_ret_flush_l1d_recalc();
x86_rngds_mitg_recalculate(true);
mca_resume();
if (vmm_resume_p != NULL)
vmm_resume_p();

2
sys/amd64/amd64/initcpu.c
View File

@ -313,7 +313,7 @@ initializecpu(void)
}
load_cr4(cr4);
/* Reload cpu ext features to reflect cr4 changes */
if (IS_BSP())
if (IS_BSP() && cold)
identify_cpu_ext_features();
if (IS_BSP() && (amd_feature & AMDID_NX) != 0) {
msr = rdmsr(MSR_EFER) | EFER_NXE;