[PATCH 1/1 FYI] tools arch x86: Sync the msr-index.h copy with the kernel sources to pick IA32_MKTME_KEYID_PARTITIONING
From: Arnaldo Carvalho de Melo
Date: Thu Jan 25 2024 - 09:19:18 EST
tldr; Just FYI, I'm carrying this on the perf tools tree.
- Arnaldo
Full explanation:
There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.
The way these headers are used in perf are not restricted to just
including them to compile something.
There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.
E.g.:
$ ls -1 tools/perf/trace/beauty/*.sh | head -5
tools/perf/trace/beauty/arch_errno_names.sh
tools/perf/trace/beauty/drm_ioctl.sh
tools/perf/trace/beauty/fadvise.sh
tools/perf/trace/beauty/fsconfig.sh
tools/perf/trace/beauty/fsmount.sh
$
$ tools/perf/trace/beauty/fadvise.sh
static const char *fadvise_advices[] = {
[0] = "NORMAL",
[1] = "RANDOM",
[2] = "SEQUENTIAL",
[3] = "WILLNEED",
[4] = "DONTNEED",
[5] = "NOREUSE",
};
$
The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.
So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.
---
To pick up the changes in:
765a0542fdc7aad7 ("x86/virt/tdx: Detect TDX during kernel boot")
Addressing this tools/perf build warning:
Warning: Kernel ABI header differences:
diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
That makes the beautification scripts to pick some new entries:
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > before
$ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > after
$ diff -u before after
--- before 2024-01-25 11:08:12.363223880 -0300
+++ after 2024-01-25 11:08:24.839307699 -0300
@@ -21,6 +21,7 @@
[0x0000004f] = "PPIN",
[0x00000060] = "LBR_CORE_TO",
[0x00000079] = "IA32_UCODE_WRITE",
+ [0x00000087] = "IA32_MKTME_KEYID_PARTITIONING",
[0x0000008b] = "AMD64_PATCH_LEVEL",
[0x0000008C] = "IA32_SGXLEPUBKEYHASH0",
[0x0000008D] = "IA32_SGXLEPUBKEYHASH1",
$
Now one can trace systemwide asking to see backtraces to where that MSR
is being read/written, see this example with a previous update:
# perf trace -e msr:*_msr/max-stack=32/ --filter="msr==IA32_MKTME_KEYID_PARTITIONING"
^C#
If we use -v (verbose mode) we can see what it does behind the scenes:
# perf trace -v -e msr:*_msr/max-stack=32/ --filter="msr==IA32_MKTME_KEYID_PARTITIONING"
Using CPUID GenuineIntel-6-8E-A
0x87
New filter for msr:read_msr: (msr==0x87) && (common_pid != 58627 && common_pid != 3792)
0x87
New filter for msr:write_msr: (msr==0x87) && (common_pid != 58627 && common_pid != 3792)
mmap size 528384B
^C#
Example with a frequent msr:
# perf trace -v -e msr:*_msr/max-stack=32/ --filter="msr==IA32_SPEC_CTRL" --max-events 2
Using CPUID AuthenticAMD-25-21-0
0x48
New filter for msr:read_msr: (msr==0x48) && (common_pid != 2612129 && common_pid != 3841)
0x48
New filter for msr:write_msr: (msr==0x48) && (common_pid != 2612129 && common_pid != 3841)
mmap size 528384B
Looking at the vmlinux_path (8 entries long)
symsrc__init: build id mismatch for vmlinux.
Using /proc/kcore for kernel data
Using /proc/kallsyms for symbols
0.000 Timer/2525383 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
do_trace_write_msr ([kernel.kallsyms])
do_trace_write_msr ([kernel.kallsyms])
__switch_to_xtra ([kernel.kallsyms])
__switch_to ([kernel.kallsyms])
__schedule ([kernel.kallsyms])
schedule ([kernel.kallsyms])
futex_wait_queue_me ([kernel.kallsyms])
futex_wait ([kernel.kallsyms])
do_futex ([kernel.kallsyms])
__x64_sys_futex ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
__futex_abstimed_wait_common64 (/usr/lib64/libpthread-2.33.so)
0.030 :0/0 msr:write_msr(msr: IA32_SPEC_CTRL, val: 2)
do_trace_write_msr ([kernel.kallsyms])
do_trace_write_msr ([kernel.kallsyms])
__switch_to_xtra ([kernel.kallsyms])
__switch_to ([kernel.kallsyms])
__schedule ([kernel.kallsyms])
schedule_idle ([kernel.kallsyms])
do_idle ([kernel.kallsyms])
cpu_startup_entry ([kernel.kallsyms])
secondary_startup_64_no_verify ([kernel.kallsyms])
#
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kai Huang <kai.huang@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/arch/x86/include/asm/msr-index.h | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
index 1d51e1850ed03d46..f1bd7b91b3c63735 100644
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -237,6 +237,11 @@
#define LBR_INFO_CYCLES 0xffff
#define LBR_INFO_BR_TYPE_OFFSET 56
#define LBR_INFO_BR_TYPE (0xfull << LBR_INFO_BR_TYPE_OFFSET)
+#define LBR_INFO_BR_CNTR_OFFSET 32
+#define LBR_INFO_BR_CNTR_NUM 4
+#define LBR_INFO_BR_CNTR_BITS 2
+#define LBR_INFO_BR_CNTR_MASK GENMASK_ULL(LBR_INFO_BR_CNTR_BITS - 1, 0)
+#define LBR_INFO_BR_CNTR_FULL_MASK GENMASK_ULL(LBR_INFO_BR_CNTR_NUM * LBR_INFO_BR_CNTR_BITS - 1, 0)
#define MSR_ARCH_LBR_CTL 0x000014ce
#define ARCH_LBR_CTL_LBREN BIT(0)
@@ -536,6 +541,9 @@
#define MSR_RELOAD_PMC0 0x000014c1
#define MSR_RELOAD_FIXED_CTR0 0x00001309
+/* KeyID partitioning between MKTME and TDX */
+#define MSR_IA32_MKTME_KEYID_PARTITIONING 0x00000087
+
/*
* AMD64 MSRs. Not complete. See the architecture manual for a more
* complete list.
--
2.43.0