From: tip-bot for Ashok Raj <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: bp@suse.de, ashok.raj@intel.com, arjan.van.de.ven@intel.com,
hpa@zytor.com, mingo@kernel.org, thomas.lendacky@amd.com,
tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: [tip:x86/pti] x86/microcode/intel: Check microcode revision before updating sibling threads
Date: Thu, 8 Mar 2018 01:25:47 -0800 [thread overview]
Message-ID: <tip-c182d2b7d0ca48e0d6ff16f7d883161238c447ed@git.kernel.org> (raw)
In-Reply-To: <20180228102846.13447-3-bp@alien8.de>
Commit-ID: c182d2b7d0ca48e0d6ff16f7d883161238c447ed
Gitweb: https://git.kernel.org/tip/c182d2b7d0ca48e0d6ff16f7d883161238c447ed
Author: Ashok Raj <ashok.raj@intel.com>
AuthorDate: Wed, 28 Feb 2018 11:28:41 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 8 Mar 2018 10:19:25 +0100
x86/microcode/intel: Check microcode revision before updating sibling threads
After updating microcode on one of the threads of a core, the other
thread sibling automatically gets the update since the microcode
resources on a hyperthreaded core are shared between the two threads.
Check the microcode revision on the CPU before performing a microcode
update and thus save us the WRMSR 0x79 because it is a particularly
expensive operation.
[ Borislav: Massage changelog and coding style. ]
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Ashok Raj <ashok.raj@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Link: http://lkml.kernel.org/r/1519352533-15992-2-git-send-email-ashok.raj@intel.com
Link: https://lkml.kernel.org/r/20180228102846.13447-3-bp@alien8.de
---
arch/x86/kernel/cpu/microcode/intel.c | 27 ++++++++++++++++++++++++---
1 file changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 923054a6b760..87bd6dc94081 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -589,6 +589,17 @@ static int apply_microcode_early(struct ucode_cpu_info *uci, bool early)
if (!mc)
return 0;
+ /*
+ * Save us the MSR write below - which is a particular expensive
+ * operation - when the other hyperthread has updated the microcode
+ * already.
+ */
+ rev = intel_get_microcode_revision();
+ if (rev >= mc->hdr.rev) {
+ uci->cpu_sig.rev = rev;
+ return UCODE_OK;
+ }
+
/* write microcode via MSR 0x79 */
native_wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
@@ -776,7 +787,7 @@ static enum ucode_state apply_microcode_intel(int cpu)
{
struct microcode_intel *mc;
struct ucode_cpu_info *uci;
- struct cpuinfo_x86 *c;
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
static int prev_rev;
u32 rev;
@@ -793,6 +804,18 @@ static enum ucode_state apply_microcode_intel(int cpu)
return UCODE_NFOUND;
}
+ /*
+ * Save us the MSR write below - which is a particular expensive
+ * operation - when the other hyperthread has updated the microcode
+ * already.
+ */
+ rev = intel_get_microcode_revision();
+ if (rev >= mc->hdr.rev) {
+ uci->cpu_sig.rev = rev;
+ c->microcode = rev;
+ return UCODE_OK;
+ }
+
/* write microcode via MSR 0x79 */
wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
@@ -813,8 +836,6 @@ static enum ucode_state apply_microcode_intel(int cpu)
prev_rev = rev;
}
- c = &cpu_data(cpu);
-
uci->cpu_sig.rev = rev;
c->microcode = rev;
next prev parent reply other threads:[~2018-03-08 9:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-28 10:28 [PATCH 0/7] x86/microcode: Improve late loading Borislav Petkov
2018-02-28 10:28 ` [PATCH 1/7] x86/microcode: Get rid of struct apply_microcode_ctx Borislav Petkov
2018-03-08 9:25 ` [tip:x86/pti] " tip-bot for Borislav Petkov
2018-02-28 10:28 ` [PATCH 2/7] x86/microcode/intel: Check microcode revision before updating sibling threads Borislav Petkov
2018-03-08 9:25 ` tip-bot for Ashok Raj [this message]
2018-02-28 10:28 ` [PATCH 3/7] x86/microcode/intel: Writeback and invalidate caches before updating microcode Borislav Petkov
2018-03-08 9:26 ` [tip:x86/pti] " tip-bot for Ashok Raj
2018-02-28 10:28 ` [PATCH 4/7] x86/microcode: Do not upload microcode if CPUs are offline Borislav Petkov
2018-02-28 13:11 ` Henrique de Moraes Holschuh
2018-02-28 13:26 ` Raj, Ashok
2018-02-28 19:07 ` Henrique de Moraes Holschuh
2018-03-05 22:06 ` Tom Lendacky
2018-03-08 9:26 ` [tip:x86/pti] " tip-bot for Ashok Raj
2018-02-28 10:28 ` [PATCH 5/7] x86/microcode/intel: Look into the patch cache first Borislav Petkov
2018-03-08 9:27 ` [tip:x86/pti] " tip-bot for Borislav Petkov
2018-02-28 10:28 ` [PATCH 6/7] x86/microcode: Request microcode on the BSP Borislav Petkov
2018-03-05 22:08 ` Tom Lendacky
2018-03-08 9:27 ` [tip:x86/pti] " tip-bot for Borislav Petkov
2018-02-28 10:28 ` [PATCH 7/7] x86/microcode: Synchronize late microcode loading Borislav Petkov
2018-02-28 13:59 ` Henrique de Moraes Holschuh
2018-02-28 14:08 ` Borislav Petkov
2018-02-28 17:48 ` Henrique de Moraes Holschuh
2018-03-05 22:09 ` Tom Lendacky
2018-03-08 9:28 ` [tip:x86/pti] " tip-bot for Ashok Raj
2018-03-05 22:12 ` [PATCH 0/7] x86/microcode: Improve late loading Tom Lendacky
2018-03-05 23:51 ` Raj, Ashok
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