Add Bus Lock Detect (called Bus Lock Trap in AMD docs) support for AMD
platforms. Bus Lock Detect is enumerated with 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].
Patches are prepared on tip/master (435dfff07e5b).
[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
v2: https://lore.kernel.org/r/20240712093943.1288-1-ravi.bangoria@xxxxxxx
v2->v3:
- Fix build failure reported by LKP test bot
- Reword commit messages
Note:
A Qemu fix is also require to handle a corner case where a hardware
instruction or data breakpoint is created by Qemu remote debugger (gdb)
on the same instruction which also causes a Bus Lock. Qemu patch to
handle it can be found at:
https://lore.kernel.org/r/20240712095208.1553-1-ravi.bangoria@xxxxxxx
Ravi Bangoria (4):
x86/split_lock: Move Split and Bus lock code to a dedicated file
x86/bus_lock: Add support for AMD
KVM: SVM: Don't advertise Bus Lock Detect to guest if SVM support is
missing
KVM: SVM: Add Bus Lock Detect support
arch/x86/include/asm/cpu.h | 12 +-
arch/x86/kernel/cpu/Makefile | 1 +
arch/x86/kernel/cpu/bus_lock.c | 410 +++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/common.c | 2 +
arch/x86/kernel/cpu/intel.c | 407 --------------------------------
arch/x86/kvm/svm/nested.c | 3 +-
arch/x86/kvm/svm/svm.c | 16 +-
include/linux/sched.h | 2 +-
8 files changed, 440 insertions(+), 413 deletions(-)
create mode 100644 arch/x86/kernel/cpu/bus_lock.c
--
2.34.1
