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735a6dd022
Explicitly set X86_FEATURE_OSPKE via set_cpu_cap() instead of calling
get_cpu_cap() to pull the feature bit from CPUID after enabling CR4.PKE.
Invoking get_cpu_cap() effectively wipes out any {set,clear}_cpu_cap()
changes that were made between this_cpu->c_init() and setup_pku(), as
all non-synthetic feature words are reinitialized from the CPU's CPUID
values.
Blasting away capability updates manifests most visibility when running
on a VMX capable CPU, but with VMX disabled by BIOS. To indicate that
VMX is disabled, init_ia32_feat_ctl() clears X86_FEATURE_VMX, using
clear_cpu_cap() instead of setup_clear_cpu_cap() so that KVM can report
which CPU is misconfigured (KVM needs to probe every CPU anyways).
Restoring X86_FEATURE_VMX from CPUID causes KVM to think VMX is enabled,
ultimately leading to an unexpected #GP when KVM attempts to do VMXON.
Arguably, init_ia32_feat_ctl() should use setup_clear_cpu_cap() and let
KVM figure out a different way to report the misconfigured CPU, but VMX
is not the only feature bit that is affected, i.e. there is precedent
that tweaking feature bits via {set,clear}_cpu_cap() after ->c_init()
is expected to work. Most notably, x86_init_rdrand()'s clearing of
X86_FEATURE_RDRAND when RDRAND malfunctions is also overwritten.
Fixes:
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|---|---|---|
| .. | ||
| mce | ||
| microcode | ||
| mtrr | ||
| resctrl | ||
| .gitignore | ||
| acrn.c | ||
| amd.c | ||
| aperfmperf.c | ||
| bugs.c | ||
| cacheinfo.c | ||
| centaur.c | ||
| common.c | ||
| cpu.h | ||
| cpuid-deps.c | ||
| cyrix.c | ||
| feat_ctl.c | ||
| hygon.c | ||
| hypervisor.c | ||
| intel_epb.c | ||
| intel_pconfig.c | ||
| intel.c | ||
| Makefile | ||
| match.c | ||
| mkcapflags.sh | ||
| mshyperv.c | ||
| perfctr-watchdog.c | ||
| powerflags.c | ||
| proc.c | ||
| rdrand.c | ||
| scattered.c | ||
| topology.c | ||
| transmeta.c | ||
| tsx.c | ||
| umc.c | ||
| umwait.c | ||
| vmware.c | ||
| zhaoxin.c | ||