3.18-stable review patch. If anyone has any objections, please let me know.
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From: Prarit Bhargava prarit@redhat.com
[ Upstream commit f69ffc5d3db8f1f03fd6d1df5930f9a1fbd787b6 ]
cpupower crashes on VMWare guests. The guests have the AMD PStateDef MSR (0xC0010064 + state number) set to zero. As a result fid and did are zero and the crash occurs because of a divide by zero (cof = fid/did). This can be prevented by checking the enable bit in the PStateDef MSR before calculating cof. By doing this the value of pstate[i] remains zero and the value can be tested before displaying the active Pstates.
Check the enable bit in the PstateDef register for all supported families and only print out enabled Pstates.
Signed-off-by: Prarit Bhargava prarit@redhat.com Cc: Shuah Khan shuah@kernel.org Cc: Stafford Horne shorne@gmail.com Signed-off-by: Shuah Khan (Samsung OSG) shuah@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/power/cpupower/utils/cpufreq-info.c | 2 ++ tools/power/cpupower/utils/helpers/amd.c | 5 +++++ 2 files changed, 7 insertions(+)
--- a/tools/power/cpupower/utils/cpufreq-info.c +++ b/tools/power/cpupower/utils/cpufreq-info.c @@ -200,6 +200,8 @@ static int get_boost_mode(unsigned int c printf(_(" Boost States: %d\n"), b_states); printf(_(" Total States: %d\n"), pstate_no); for (i = 0; i < pstate_no; i++) { + if (!pstates[i]) + continue; if (i < b_states) printf(_(" Pstate-Pb%d: %luMHz (boost state)" "\n"), i, pstates[i]); --- a/tools/power/cpupower/utils/helpers/amd.c +++ b/tools/power/cpupower/utils/helpers/amd.c @@ -103,6 +103,11 @@ int decode_pstates(unsigned int cpu, uns } if (read_msr(cpu, MSR_AMD_PSTATE + i, &pstate.val)) return -1; + if ((cpu_family == 0x17) && (!pstate.fam17h_bits.en)) + continue; + else if (!pstate.bits.en) + continue; + pstates[i] = get_cof(cpu_family, pstate); } *no = i;