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Date: Tue, 25 Jul 2017 08:55:24 -0400 From: Prarit Bhargava <prarit@...hat.com> To: linux-kernel@...r.kernel.org Cc: Prarit Bhargava <prarit@...hat.com>, Len Brown <len.brown@...el.com>, Len Brown <lenb@...nel.org> Subject: [PATCH] turbostat: Running on virtual machine is not supported When running turbostat on a virtual machine the error turbostat: msr 0 offset 0xe2 read failed: Input/output error is output to the user. /dev/msr and perf do not work on a virtual machine. turbostat is dependent on that support so turbostat does not work either. A common way of determining if the system is a virtual machine is to search /proc/cpuinfo flags entry for "hypervisor". turbostat must output a proper error message when found. Signed-off-by: Prarit Bhargava <prarit@...hat.com> Cc: Len Brown <len.brown@...el.com> Cc: Len Brown <lenb@...nel.org> --- tools/power/x86/turbostat/turbostat.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c index 0dafba2c1e7d..ca1ea68bc4e8 100644 --- a/tools/power/x86/turbostat/turbostat.c +++ b/tools/power/x86/turbostat/turbostat.c @@ -5088,6 +5088,34 @@ void cmdline(int argc, char **argv) } } +int has_hypervisor(void) +{ + FILE *cpuinfo; + char *flags, *hypervisor; + char *buffer; + + /* On VMs /proc/cpuinfo contains a "flags" entry for hypervisor */ + cpuinfo = fopen_or_die("/proc/cpuinfo", "ro"); + + buffer = malloc(4096); + if (!buffer) + err(-ENOMEM, "buffer malloc fail"); + + fread(buffer, 1024, 1, cpuinfo); + + flags = strstr(buffer, "flags"); + rewind(cpuinfo); + fseek(cpuinfo, flags - buffer, SEEK_SET); + fgets(buffer, 4096, cpuinfo); + fclose(cpuinfo); + + hypervisor = strstr(buffer, "hypervisor"); + + free(buffer); + + return !!hypervisor; +} + int main(int argc, char **argv) { outf = stderr; @@ -5097,6 +5125,12 @@ int main(int argc, char **argv) if (!quiet) print_version(); + if (has_hypervisor()) { + fprintf(outf, + "turbostat is not supported on virtual machines.\n"); + return -ENXIO; + } + probe_sysfs(); turbostat_init(); -- 1.8.5.5
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