[PATCH v5 11/19] x86/cpu: Print VMX flags in /proc/cpuinfo using VMX_FEATURES_*

Sean Christopherson
2019-12-21T04:46:57Z

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>
---
arch/x86/boot/mkcpustr.c | 1 +
arch/x86/kernel/cpu/Makefile | 5 +++--
arch/x86/kernel/cpu/mkcapflags.sh | 15 +++++++++++----
arch/x86/kernel/cpu/proc.c | 15 +++++++++++++++
4 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/mkcpustr.c b/arch/x86/boot/mkcpustr.c
index 9caa10e82217..da0ccc5de538 100644
--- a/arch/x86/boot/mkcpustr.c
+++ b/arch/x86/boot/mkcpustr.c
@@ -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)
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 4173b0de7a2f..dba6a83bc349 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -57,11 +57,12 @@ 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
diff --git a/arch/x86/kernel/cpu/mkcapflags.sh b/arch/x86/kernel/cpu/mkcapflags.sh
index aed45b8895d5..1db560ed2ca3 100644
--- a/arch/x86/kernel/cpu/mkcapflags.sh
+++ b/arch/x86/kernel/cpu/mkcapflags.sh
@@ -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
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index cb2e49810d68..4eec8889b0ff 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -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;
--
2.24.1