| Message ID | 20241001063413.687787-2-manali.shukla@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for the Bus Lock Threshold | expand |
On Tue, Oct 01, 2024, Manali Shukla wrote: > Add support for generating Virtualization feature names in capflags.c > and use the resulting x86_virt_flags to print the virt flags in > /proc/cpuinfo. > > Currently, it is difficult to check if a feature is supported in _KVM_. > Manually querying cpuid to know whether the feature is supported or not > can be quite tedious at times. > > Print the features supported in KVM hypervisor in a dedicated "virt" > line instead of adding them to the common "flags". First off, printing flags in a separate section doesn't magically connect them to KVM support. E.g. if you cut this series after patch 2, BUS_LOCK_THRESHOLD will show up in "virt" despite KVM not supporting the feature. Second, deviating from the X86_FEATURE_* syntax will make it _harder_ for KVM to manage its configuration. Third, this is completely orthogonal to supporting bus lock threshold in KVM, i.e. belongs in a separate series.
On 10/1/2024 10:11 PM, Sean Christopherson wrote: > On Tue, Oct 01, 2024, Manali Shukla wrote: >> Add support for generating Virtualization feature names in capflags.c >> and use the resulting x86_virt_flags to print the virt flags in >> /proc/cpuinfo. >> >> Currently, it is difficult to check if a feature is supported in _KVM_. >> Manually querying cpuid to know whether the feature is supported or not >> can be quite tedious at times. >> >> Print the features supported in KVM hypervisor in a dedicated "virt" >> line instead of adding them to the common "flags". > > First off, printing flags in a separate section doesn't magically connect them > to KVM support. E.g. if you cut this series after patch 2, BUS_LOCK_THRESHOLD > will show up in "virt" despite KVM not supporting the feature. > > Second, deviating from the X86_FEATURE_* syntax will make it _harder_ for KVM to > manage its configuration. > > Third, this is completely orthogonal to supporting bus lock threshold in KVM, > i.e. belongs in a separate series. Okay. I agree to your point. I will remove the patch from this series. -Manali
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 0b9611da6c53..74c52bfd8cf2 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -41,6 +41,7 @@ enum cpuid_leafs #define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31) extern const char * const x86_cap_flags[NCAPINTS*32]; +extern const char * const x86_virt_flags[NCAPINTS*32]; extern const char * const x86_power_flags[32]; #define X86_CAP_FMT "%s" #define x86_cap_flag(flag) x86_cap_flags[flag] diff --git a/arch/x86/kernel/cpu/mkcapflags.sh b/arch/x86/kernel/cpu/mkcapflags.sh index 68f537347466..3671c7892c56 100644 --- a/arch/x86/kernel/cpu/mkcapflags.sh +++ b/arch/x86/kernel/cpu/mkcapflags.sh @@ -62,6 +62,9 @@ trap 'rm "$OUT"' EXIT dump_array "x86_bug_flags" "NBUGINTS*32" "X86_BUG_" "NCAPINTS*32" $2 echo "" + dump_array "x86_virt_flags" "NCAPINTS*32" "X86_VIRT_FEATURE_" "" $2 + echo "" + echo "#ifdef CONFIG_X86_VMX_FEATURE_NAMES" echo "#ifndef _ASM_X86_VMXFEATURES_H" echo "#include <asm/vmxfeatures.h>" diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index e65fae63660e..3068b0a110e4 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -103,6 +103,11 @@ 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]); + seq_puts(m, "\nvirt\t\t:"); + for (i = 0; i < 32*NCAPINTS; i++) + if (cpu_has(c, i) && x86_virt_flags[i] != NULL) + seq_printf(m, " %s", x86_virt_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:");
Add support for generating Virtualization feature names in capflags.c and use the resulting x86_virt_flags to print the virt flags in /proc/cpuinfo. Currently, it is difficult to check if a feature is supported in _KVM_. Manually querying cpuid to know whether the feature is supported or not can be quite tedious at times. Print the features supported in KVM hypervisor in a dedicated "virt" line instead of adding them to the common "flags". To do so, define flags which are needed to be added in a dedicated virt line in /proc/cpuinfo with prefix X86_VIRT_FEATURE_. Signed-off-by: Manali Shukla <manali.shukla@amd.com> --- arch/x86/include/asm/cpufeature.h | 1 + arch/x86/kernel/cpu/mkcapflags.sh | 3 +++ arch/x86/kernel/cpu/proc.c | 5 +++++ 3 files changed, 9 insertions(+)