From: Borislav Petkov <bp@alien8.de>
To: X86 ML <x86@kernel.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 1/3] x86/msr: Pass a single MSR value to __rwmsr_on_cpus() too
Date: Wed, 10 Jun 2020 13:00:35 +0200 [thread overview]
Message-ID: <20200610110037.11853-2-bp@alien8.de> (raw)
In-Reply-To: <20200610110037.11853-1-bp@alien8.de>
From: Borislav Petkov <bp@suse.de>
__rwmsr_on_cpus() is the low-level worker function which is called by
the exported {rd,wr}msr_on_cpus() when an MSR is supposed to be set with
values for CPUs or an MSR is supposed to be read from CPUs into an array
of percpu variables in @msrs.
The low-level machinery supports also passing a single MSR value for the
single CPU {rd,wr}msr_on_cpu() handlers.
Pass that value to __rwmsr_on_cpus() too and enforce a mutually
exclusive either a single MSR value "XOR" an array of per-CPU MSR
values.
This is the prerequisite for supporting writing the same MSR value on
multiple CPUs.
Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/lib/msr-smp.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/x86/lib/msr-smp.c b/arch/x86/lib/msr-smp.c
index fee8b9c0520c..15e1157d6b29 100644
--- a/arch/x86/lib/msr-smp.c
+++ b/arch/x86/lib/msr-smp.c
@@ -97,7 +97,7 @@ int wrmsrl_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
EXPORT_SYMBOL(wrmsrl_on_cpu);
static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no,
- struct msr *msrs,
+ struct msr *msrs, u64 reg_val,
void (*msr_func) (void *info))
{
struct msr_info rv;
@@ -105,8 +105,13 @@ static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no,
memset(&rv, 0, sizeof(rv));
+ /* Can't have both. */
+ if (WARN_ON(msrs && reg_val))
+ return;
+
rv.msrs = msrs;
rv.msr_no = msr_no;
+ rv.reg.q = reg_val;
this_cpu = get_cpu();
@@ -126,7 +131,7 @@ static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no,
*/
void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs)
{
- __rwmsr_on_cpus(mask, msr_no, msrs, __rdmsr_on_cpu);
+ __rwmsr_on_cpus(mask, msr_no, msrs, 0, __rdmsr_on_cpu);
}
EXPORT_SYMBOL(rdmsr_on_cpus);
@@ -140,7 +145,7 @@ EXPORT_SYMBOL(rdmsr_on_cpus);
*/
void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr *msrs)
{
- __rwmsr_on_cpus(mask, msr_no, msrs, __wrmsr_on_cpu);
+ __rwmsr_on_cpus(mask, msr_no, msrs, 0, __wrmsr_on_cpu);
}
EXPORT_SYMBOL(wrmsr_on_cpus);
--
2.21.0
next prev parent reply other threads:[~2020-06-10 11:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 11:00 [PATCH 0/3] x86/MSR: Add a MSR write callback Borislav Petkov
2020-06-10 11:00 ` Borislav Petkov [this message]
2020-06-10 11:00 ` [PATCH 2/3] x86/msr: Add wrmsrl_val_on_cpus() Borislav Petkov
2020-06-10 11:00 ` [PATCH 3/3] x86/msr: Add an MSR write callback Borislav Petkov
2020-06-10 12:32 ` Peter Zijlstra
2020-06-10 13:21 ` Borislav Petkov
2020-06-10 14:01 ` Peter Zijlstra
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