On 06-May-24 9:54 PM, Jim Mattson wrote: > On Sun, Apr 28, 2024 at 11:08 PM Ravi Bangoria <ravi.bangoria@xxxxxxx> wrote: >> >> Upcoming AMD uarch will support Bus Lock Detect (called Bus Lock Trap >> in AMD docs). Add support for the same in Linux. Bus Lock Detect is >> enumerated with cpuid CPUID Fn0000_0007_ECX_x0 bit [24 / BUSLOCKTRAP]. >> It can be enabled through MSR_IA32_DEBUGCTLMSR. When enabled, hardware >> clears DR6[11] and raises a #DB exception on occurrence of Bus Lock if >> CPL > 0. More detail about the feature can be found in AMD APM[1]. >> >> [1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June >> 2023, Vol 2, 13.1.3.6 Bus Lock Trap >> https://bugzilla.kernel.org/attachment.cgi?id=304653 > > Is there any chance of getting something similar to Intel's "VMM > bus-lock detection," which causes a trap-style VM-exit on a bus lock > event? You are probably asking about "Bus Lock Threshold". Please see "15.14.5 Bus Lock Threshold" in the same doc. fwiw, Bus Lock Threshold is of fault style. Thanks, Ravi
