On October 4, 2024 7:33:38 AM GMT+02:00, Manali Shukla <manali.shukla@xxxxxxx> wrote: >Misbehaving guests can cause bus locks to degrade the performance of >the system. The Bus Lock Threshold feature can be used to address this >issue by providing capability to the hypervisor to limit guest's >ability to generate bus lock, thereby preventing system slowdown due >to performance penalities. > >When the Bus Lock Threshold feature is enabled, the processor checks >the bus lock threshold count before executing the buslock and decides >whether to trigger bus lock exit or not. > >The value of the bus lock threshold count '0' generates bus lock >exits, and if the value is greater than '0', the bus lock is executed >successfully and the bus lock threshold count is decremented. > >Presence of the Bus Lock threshold feature is indicated via CPUID >function 0x8000000A_EDX[29]. > >Signed-off-by: Manali Shukla <manali.shukla@xxxxxxx> >--- > arch/x86/include/asm/cpufeatures.h | 1 + > 1 file changed, 1 insertion(+) > >diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h >index dd4682857c12..77fa8e743ccc 100644 >--- a/arch/x86/include/asm/cpufeatures.h >+++ b/arch/x86/include/asm/cpufeatures.h >@@ -382,6 +382,7 @@ > #define X86_FEATURE_V_SPEC_CTRL (15*32+20) /* "v_spec_ctrl" Virtual SPEC_CTRL */ > #define X86_FEATURE_VNMI (15*32+25) /* "vnmi" Virtual NMI */ > #define X86_FEATURE_SVME_ADDR_CHK (15*32+28) /* SVME addr check */ >+#define X86_FEATURE_BUS_LOCK_THRESHOLD (15*32+29) /* "buslock" Bus lock threshold */ Why does this feature flag need to be visible in /proc/cpuinfo? -- Sent from a small device: formatting sucks and brevity is inevitable.
