* Xin Li <x...@zytor.com> wrote:
> On 4/1/2025 12:52 AM, Ingo Molnar wrote:
> > > Should we rename the *msrl() functions to *msrq() as part of this
> > > overhaul?
> > Yeah, that's a good idea, and because talk is cheap I just implemented
> > this in the tip:WIP.x86/msr branch with a couple of other cleanups in
> > this area (see the shortlog & diffstat below), but the churn is high:
> >
> > 144 files changed, 1034 insertions(+), 1034 deletions(-)
>
> Hi Ingo,
>
> I noticed that you keep the type of MSR index in these patches as
> "unsigned int".
>
> I'm thinking would it be better to standardize it as "u32"?
>
> Because:
> 1) MSR index is placed in ECX to execute MSR instructions, and the
> high-order 32 bits of RCX are ignored on 64-bit.
> 2) MSR index is encoded as a 32-bit immediate in the new immediate form
> MSR instructions.
Makes sense - something like the attached patch?
Thanks,
Ingo
=====================>
From: Ingo Molnar <mi...@kernel.org>
Date: Wed, 9 Apr 2025 21:12:39 +0200
Subject: [PATCH] x86/msr: Standardize on 'u32' MSR indices in <asm/msr.h>
This is the customary type used for hardware ABIs.
Suggested-by: Xin Li <x...@zytor.com>
Suggested-by: "H. Peter Anvin" <h...@zytor.com>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
arch/x86/include/asm/msr.h | 29 ++++++++++++++---------------
arch/x86/lib/msr.c | 4 ++--
2 files changed, 16 insertions(+), 17 deletions(-)
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 4ee9ae734c08..20deb58308e5 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -63,12 +63,12 @@ struct saved_msrs {
DECLARE_TRACEPOINT(read_msr);
DECLARE_TRACEPOINT(write_msr);
DECLARE_TRACEPOINT(rdpmc);
-extern void do_trace_write_msr(unsigned int msr, u64 val, int failed);
-extern void do_trace_read_msr(unsigned int msr, u64 val, int failed);
+extern void do_trace_write_msr(u32 msr, u64 val, int failed);
+extern void do_trace_read_msr(u32 msr, u64 val, int failed);
extern void do_trace_rdpmc(u32 msr, u64 val, int failed);
#else
-static inline void do_trace_write_msr(unsigned int msr, u64 val, int failed) {}
-static inline void do_trace_read_msr(unsigned int msr, u64 val, int failed) {}
+static inline void do_trace_write_msr(u32 msr, u64 val, int failed) {}
+static inline void do_trace_read_msr(u32 msr, u64 val, int failed) {}
static inline void do_trace_rdpmc(u32 msr, u64 val, int failed) {}
#endif
@@ -79,7 +79,7 @@ static inline void do_trace_rdpmc(u32 msr, u64 val, int
failed) {}
* think of extending them - you will be slapped with a stinking trout or a
frozen
* shark will reach you, wherever you are! You've been warned.
*/
-static __always_inline u64 __rdmsr(unsigned int msr)
+static __always_inline u64 __rdmsr(u32 msr)
{
DECLARE_ARGS(val, low, high);
@@ -91,7 +91,7 @@ static __always_inline u64 __rdmsr(unsigned int msr)
return EAX_EDX_VAL(val, low, high);
}
-static __always_inline void __wrmsr(unsigned int msr, u32 low, u32 high)
+static __always_inline void __wrmsr(u32 msr, u32 low, u32 high)
{
asm volatile("1: wrmsr\n"
"2:\n"
@@ -113,7 +113,7 @@ do {
\
__wrmsr((msr), (u32)((u64)(val)), \
(u32)((u64)(val) >> 32))
-static inline u64 native_read_msr(unsigned int msr)
+static inline u64 native_read_msr(u32 msr)
{
u64 val;
@@ -125,8 +125,7 @@ static inline u64 native_read_msr(unsigned int msr)
return val;
}
-static inline u64 native_read_msr_safe(unsigned int msr,
- int *err)
+static inline u64 native_read_msr_safe(u32 msr, int *err)
{
DECLARE_ARGS(val, low, high);
@@ -142,7 +141,7 @@ static inline u64 native_read_msr_safe(unsigned int msr,
/* Can be uninlined because referenced by paravirt */
static inline void notrace
-native_write_msr(unsigned int msr, u32 low, u32 high)
+native_write_msr(u32 msr, u32 low, u32 high)
{
__wrmsr(msr, low, high);
@@ -152,7 +151,7 @@ native_write_msr(unsigned int msr, u32 low, u32 high)
/* Can be uninlined because referenced by paravirt */
static inline int notrace
-native_write_msr_safe(unsigned int msr, u32 low, u32 high)
+native_write_msr_safe(u32 msr, u32 low, u32 high)
{
int err;
@@ -251,7 +250,7 @@ do {
\
(void)((high) = (u32)(__val >> 32)); \
} while (0)
-static inline void wrmsr(unsigned int msr, u32 low, u32 high)
+static inline void wrmsr(u32 msr, u32 low, u32 high)
{
native_write_msr(msr, low, high);
}
@@ -259,13 +258,13 @@ static inline void wrmsr(unsigned int msr, u32 low, u32
high)
#define rdmsrq(msr, val) \
((val) = native_read_msr((msr)))
-static inline void wrmsrq(unsigned int msr, u64 val)
+static inline void wrmsrq(u32 msr, u64 val)
{
native_write_msr(msr, (u32)(val & 0xffffffffULL), (u32)(val >> 32));
}
/* wrmsr with exception handling */
-static inline int wrmsr_safe(unsigned int msr, u32 low, u32 high)
+static inline int wrmsr_safe(u32 msr, u32 low, u32 high)
{
return native_write_msr_safe(msr, low, high);
}
@@ -280,7 +279,7 @@ static inline int wrmsr_safe(unsigned int msr, u32 low, u32
high)
__err; \
})
-static inline int rdmsrq_safe(unsigned int msr, u64 *p)
+static inline int rdmsrq_safe(u32 msr, u64 *p)
{
int err;
diff --git a/arch/x86/lib/msr.c b/arch/x86/lib/msr.c
index e18925899f13..4ef7c6dcbea6 100644
--- a/arch/x86/lib/msr.c
+++ b/arch/x86/lib/msr.c
@@ -122,14 +122,14 @@ int msr_clear_bit(u32 msr, u8 bit)
EXPORT_SYMBOL_GPL(msr_clear_bit);
#ifdef CONFIG_TRACEPOINTS
-void do_trace_write_msr(unsigned int msr, u64 val, int failed)
+void do_trace_write_msr(u32 msr, u64 val, int failed)
{
trace_write_msr(msr, val, failed);
}
EXPORT_SYMBOL(do_trace_write_msr);
EXPORT_TRACEPOINT_SYMBOL(write_msr);
-void do_trace_read_msr(unsigned int msr, u64 val, int failed)
+void do_trace_read_msr(u32 msr, u64 val, int failed)
{
trace_read_msr(msr, val, failed);
}
