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x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_*

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Add support for generating VMX feature names in capflags.c and use the
resulting x86_vmx_flags to print the VMX flags in /proc/cpuinfo.  Don't
print VMX flags if no bits are set in word 0, which holds Pin Controls.
Pin Control's INTR and NMI exiting are fundamental pillars of VMX, if
they are not supported then the CPU is broken, it does not actually
support VMX, or the kernel wasn't built with support for the target CPU.

Print the features in a dedicated "vmx flags" line to avoid polluting
the common "flags" and to avoid having to prefix all flags with "vmx_",
which results in horrendously long names.

Keep synthetic VMX flags in cpufeatures to preserve /proc/cpuinfo's ABI
for those flags.  This means that "flags" and "vmx flags" will have
duplicate entries for tpr_shadow (virtual_tpr), vnmi, ept, flexpriority,
vpid and ept_ad, but caps the pollution of "flags" at those six VMX
features.  The vendor-specific code that populates the synthetic flags
will be consolidated in a future patch to further minimize the lasting
damage.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-12-sean.j.christopherson@intel.com
This commit is contained in:
Sean Christopherson 2019-12-20 20:45:05 -08:00 committed by Borislav Petkov
parent b47ce1fed4
commit 14442a159c
4 changed files with 30 additions and 6 deletions
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1
arch/x86/boot/mkcpustr.c
View File

@ -15,6 +15,7 @@
#include "../include/asm/required-features.h"
#include "../include/asm/disabled-features.h"
#include "../include/asm/cpufeatures.h"
#include "../include/asm/vmxfeatures.h"
#include "../kernel/cpu/capflags.c"
int main(void)

5
arch/x86/kernel/cpu/Makefile
View File

@ -54,11 +54,12 @@ obj-$(CONFIG_ACRN_GUEST) += acrn.o
ifdef CONFIG_X86_FEATURE_NAMES
quiet_cmd_mkcapflags = MKCAP $@
cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $< $@
cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $@ $^
cpufeature = $(src)/../../include/asm/cpufeatures.h
vmxfeature = $(src)/../../include/asm/vmxfeatures.h
$(obj)/capflags.c: $(cpufeature) $(src)/mkcapflags.sh FORCE
$(obj)/capflags.c: $(cpufeature) $(vmxfeature) $(src)/mkcapflags.sh FORCE
$(call if_changed,mkcapflags)
endif
targets += capflags.c

15
arch/x86/kernel/cpu/mkcapflags.sh
View File

@ -6,8 +6,7 @@
set -e
IN=$1
OUT=$2
OUT=$1
dump_array()
{
@ -15,6 +14,7 @@ dump_array()
SIZE=$2
PFX=$3
POSTFIX=$4
IN=$5
PFX_SZ=$(echo $PFX | wc -c)
TABS="$(printf '\t\t\t\t\t')"
@ -57,11 +57,18 @@ trap 'rm "$OUT"' EXIT
echo "#endif"
echo ""
dump_array "x86_cap_flags" "NCAPINTS*32" "X86_FEATURE_" ""
dump_array "x86_cap_flags" "NCAPINTS*32" "X86_FEATURE_" "" $2
echo ""
dump_array "x86_bug_flags" "NBUGINTS*32" "X86_BUG_" "NCAPINTS*32"
dump_array "x86_bug_flags" "NBUGINTS*32" "X86_BUG_" "NCAPINTS*32" $2
echo ""
echo "#ifdef CONFIG_X86_VMX_FEATURE_NAMES"
echo "#ifndef _ASM_X86_VMXFEATURES_H"
echo "#include <asm/vmxfeatures.h>"
echo "#endif"
dump_array "x86_vmx_flags" "NVMXINTS*32" "VMX_FEATURE_" "" $3
echo "#endif /* CONFIG_X86_VMX_FEATURE_NAMES */"
) > $OUT
trap - EXIT

15
arch/x86/kernel/cpu/proc.c
View File

@ -7,6 +7,10 @@
#include "cpu.h"
#ifdef CONFIG_X86_VMX_FEATURE_NAMES
extern const char * const x86_vmx_flags[NVMXINTS*32];
#endif
/*
* Get CPU information for use by the procfs.
*/
@ -102,6 +106,17 @@ static int show_cpuinfo(struct seq_file *m, void *v)
if (cpu_has(c, i) && x86_cap_flags[i] != NULL)
seq_printf(m, " %s", x86_cap_flags[i]);
#ifdef CONFIG_X86_VMX_FEATURE_NAMES
if (cpu_has(c, X86_FEATURE_VMX) && c->vmx_capability[0]) {
seq_puts(m, "\nvmx flags\t:");
for (i = 0; i < 32*NVMXINTS; i++) {
if (test_bit(i, (unsigned long *)c->vmx_capability) &&
x86_vmx_flags[i] != NULL)
seq_printf(m, " %s", x86_vmx_flags[i]);
}
}
#endif
seq_puts(m, "\nbugs\t\t:");
for (i = 0; i < 32*NBUGINTS; i++) {
unsigned int bug_bit = 32*NCAPINTS + i;