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Message-Id: <20230209154156.266385-9-usama.arif@bytedance.com>
Date: Thu, 9 Feb 2023 15:41:55 +0000
From: Usama Arif <usama.arif@...edance.com>
To: dwmw2@...radead.org, tglx@...utronix.de, kim.phillips@....com
Cc: arjan@...ux.intel.com, mingo@...hat.com, bp@...en8.de,
dave.hansen@...ux.intel.com, hpa@...or.com, x86@...nel.org,
pbonzini@...hat.com, paulmck@...nel.org,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
rcu@...r.kernel.org, mimoja@...oja.de, hewenliang4@...wei.com,
thomas.lendacky@....com, seanjc@...gle.com, pmenzel@...gen.mpg.de,
fam.zheng@...edance.com, punit.agrawal@...edance.com,
simon.evans@...edance.com, liangma@...ngbit.com,
David Woodhouse <dwmw@...zon.co.uk>,
Usama Arif <usama.arif@...edance.com>
Subject: [PATCH v8 8/9] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup
From: David Woodhouse <dwmw@...zon.co.uk>
There's no need to repeatedly save the BSP's MTRRs for each AP being
brought up at boot time. And no need to use smp_call_function_single()
even for the one time they do need to be saved.
Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
Signed-off-by: Usama Arif <usama.arif@...edance.com>
---
arch/x86/kernel/cpu/mtrr/mtrr.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 783f3210d582..b6eae3ad4414 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -721,11 +721,20 @@ void __init mtrr_bp_init(void)
*/
void mtrr_save_state(void)
{
+ static bool mtrr_saved;
int first_cpu;
if (!mtrr_enabled())
return;
+ if (system_state < SYSTEM_RUNNING) {
+ if (!mtrr_saved) {
+ mtrr_save_fixed_ranges(NULL);
+ mtrr_saved = true;
+ }
+ return;
+ }
+
first_cpu = cpumask_first(cpu_online_mask);
smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);
}
--
2.25.1
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