[FYI][PATCH 1/1] tools arch x86: Sync the msr-index.h copy with the kernel sources
From: Arnaldo Carvalho de Melo
Date: Sat Nov 13 2021 - 09:19:42 EST
To pick up the changes in:
dae1bd58389615d4 ("x86/msr-index: Add MSRs for XFD")
Addressing these tools/perf build warnings:
diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h'
That makes the beautification scripts to pick some new entries:
$ diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
--- tools/arch/x86/include/asm/msr-index.h 2021-07-15 16:17:01.819817827 -0300
+++ arch/x86/include/asm/msr-index.h 2021-11-06 15:49:33.738517311 -0300
@@ -625,6 +625,8 @@
#define MSR_IA32_BNDCFGS_RSVD 0x00000ffc
+#define MSR_IA32_XFD 0x000001c4
+#define MSR_IA32_XFD_ERR 0x000001c5
#define MSR_IA32_XSS 0x00000da0
#define MSR_IA32_APICBASE 0x0000001b
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > /tmp/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 > /tmp/after
$ diff -u /tmp/before /tmp/after
--- /tmp/before 2021-11-13 11:10:39.964201505 -0300
+++ /tmp/after 2021-11-13 11:10:47.902410873 -0300
@@ -93,6 +93,8 @@
[0x000001b0] = "IA32_ENERGY_PERF_BIAS",
[0x000001b1] = "IA32_PACKAGE_THERM_STATUS",
[0x000001b2] = "IA32_PACKAGE_THERM_INTERRUPT",
+ [0x000001c4] = "IA32_XFD",
+ [0x000001c5] = "IA32_XFD_ERR",
[0x000001c8] = "LBR_SELECT",
[0x000001c9] = "LBR_TOS",
[0x000001d9] = "IA32_DEBUGCTLMSR",
$
And this gets rebuilt:
CC /tmp/build/perf/trace/beauty/tracepoints/x86_msr.o
INSTALL trace_plugins
LD /tmp/build/perf/trace/beauty/tracepoints/perf-in.o
LD /tmp/build/perf/trace/beauty/perf-in.o
LD /tmp/build/perf/perf-in.o
LINK /tmp/build/perf/perf
Now one can trace systemwide asking to see backtraces to where those
MSRs are being read/written with:
# perf trace -e msr:*_msr/max-stack=32/ --filter="msr==IA32_XFD || msr==IA32_XFD_ERR"
^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_XFD || msr==IA32_XFD_ERR"
<SNIP>
New filter for msr:read_msr: (msr==0x1c4 || msr==0x1c5) && (common_pid != 4448951 && common_pid != 8781)
New filter for msr:write_msr: (msr==0x1c4 || msr==0x1c5) && (common_pid != 4448951 && common_pid != 8781)
<SNIP>
^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 != 3738351 && common_pid != 3564)
0x48
New filter for msr:write_msr: (msr==0x48) && (common_pid != 3738351 && common_pid != 3564)
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 pipewire/2479 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])
schedule_hrtimeout_range_clock ([kernel.kallsyms])
do_epoll_wait ([kernel.kallsyms])
__x64_sys_epoll_wait ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
epoll_wait (/usr/lib64/libc-2.33.so)
[0x76c4] (/usr/lib64/spa-0.2/support/libspa-support.so)
[0x4cf0] (/usr/lib64/spa-0.2/support/libspa-support.so)
0.027 :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])
start_kernel ([kernel.kallsyms])
secondary_startup_64_no_verify ([kernel.kallsyms])
#
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/arch/x86/include/asm/msr-index.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
index a7c413432b33d85a..01e2650b958591e0 100644
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -625,6 +625,8 @@
#define MSR_IA32_BNDCFGS_RSVD 0x00000ffc
+#define MSR_IA32_XFD 0x000001c4
+#define MSR_IA32_XFD_ERR 0x000001c5
#define MSR_IA32_XSS 0x00000da0
#define MSR_IA32_APICBASE 0x0000001b
--
2.31.1