On Thu, Jan 04, 2018 at 15:58:09 +0100, Jiri Denemark wrote:
> From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>
> This new API reads host's CPU microcode version from /proc/cpuinfo.
>
> Unfortunately, there is no other way of reading microcode version which
> would be usable from both system and session daemon.
>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx>
> ---
> src/libvirt_private.syms | 1 +
> src/util/virhostcpu.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> src/util/virhostcpu.h | 2 ++
> 3 files changed, 46 insertions(+)
>
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 8d583e3e74..a705fa846d 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1869,6 +1869,7 @@ virHostCPUGetCount;
> virHostCPUGetInfo;
> virHostCPUGetKVMMaxVCPUs;
> virHostCPUGetMap;
> +virHostCPUGetMicrocodeVersion;
> virHostCPUGetOnline;
> virHostCPUGetOnlineBitmap;
> virHostCPUGetPresentBitmap;
> diff --git a/src/util/virhostcpu.c b/src/util/virhostcpu.c
> index c485a97211..713fdec553 100644
> --- a/src/util/virhostcpu.c
> +++ b/src/util/virhostcpu.c
> @@ -1206,3 +1206,46 @@ virHostCPUGetKVMMaxVCPUs(void)
> return -1;
> }
> #endif /* HAVE_LINUX_KVM_H */
> +
> +
> +#ifdef __linux__
> +
> +unsigned int
> +virHostCPUGetMicrocodeVersion(void)
> +{
> + char *outbuf = NULL;
> + char *cur;
> + unsigned int version = 0;
> +
> + if (virFileReadHeaderQuiet(CPUINFO_PATH, 4096, &outbuf) < 0) {
In other places we read 1MiB of /proc/cpuinfo:
src/util/virsysinfo.c:#define CPUINFO_FILE_LEN (1024*1024) /* 1MB limit for /proc/cpuinfo file */
Will this be enough?
> + char ebuf[1024];
> + VIR_DEBUG("Failed to read microcode version from %s: %s",
> + CPUINFO_PATH, virStrerror(errno, ebuf, sizeof(ebuf)));
Formatting the error message into a debug message does not make much
sense. I'd just log 'errno' in raw since this function does not really
return any errors.
> + return 0;
> + }
> +
> + /* Account for format 'microcode : XXXX'*/
> + if (!(cur = strstr(outbuf, "microcode")) ||
> + !(cur = strchr(cur, ':')))
> + goto cleanup;
> + cur++;
> +
> + /* Linux places the microcode revision in a 32-bit integer, so
> + * ui is fine for us too. */
> + if (virStrToLong_ui(cur, &cur, 0, &version) < 0)
> + goto cleanup;
> +
> + cleanup:
> + VIR_FREE(outbuf);
> + return version;
> +}
> +
> +#else
#else /* __linux__ */
> +
> +unsigned int
> +virHostCPUGetMicrocodeVersion(void)
> +{
> + return 0;
> +}
> +
> +#endif
#endif /* __linux__ */
> diff --git a/src/util/virhostcpu.h b/src/util/virhostcpu.h
> index 67033de842..f9f3359288 100644
> --- a/src/util/virhostcpu.h
> +++ b/src/util/virhostcpu.h
> @@ -66,4 +66,6 @@ virBitmapPtr virHostCPUGetSiblingsList(unsigned int cpu);
>
> int virHostCPUGetOnline(unsigned int cpu, bool *online);
>
> +unsigned int virHostCPUGetMicrocodeVersion(void);
> +
> #endif /* __VIR_HOSTCPU_H__*/
ACK with pointless error formatting removed.
> --
> 2.15.1
>
> --
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