From: Chao Gao <chao.gao@intel.com> To: xen-devel@lists.xenproject.org Cc: "Ashok Raj" <ashok.raj@intel.com>, "Wei Liu" <wl@xen.org>, "Andrew Cooper" <andrew.cooper3@citrix.com>, "Jan Beulich" <jbeulich@suse.com>, "Chao Gao" <chao.gao@intel.com>, "Roger Pau Monné" <roger.pau@citrix.com> Subject: [Xen-devel] [PATCH v9 15/15] microcode: block #NMI handling when loading an ucode Date: Mon, 19 Aug 2019 09:25:28 +0800 Message-ID: <1566177928-19114-16-git-send-email-chao.gao@intel.com> (raw) In-Reply-To: <1566177928-19114-1-git-send-email-chao.gao@intel.com> register an nmi callback. And this callback does busy-loop on threads which are waiting for loading completion. Control threads send NMI to slave threads to prevent NMI acceptance during ucode loading. Signed-off-by: Chao Gao <chao.gao@intel.com> --- Changes in v9: - control threads send NMI to all other threads. Slave threads will stay in the NMI handling to prevent NMI acceptance during ucode loading. Note that self-nmi is invalid according to SDM. - s/rep_nop/cpu_relax - remove debug message in microcode_nmi_callback(). Printing debug message would take long times and control thread may timeout. - rebase and fix conflicts Changes in v8: - new --- xen/arch/x86/microcode.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c index 91f9e81..d943835 100644 --- a/xen/arch/x86/microcode.c +++ b/xen/arch/x86/microcode.c @@ -38,6 +38,7 @@ #include <asm/delay.h> #include <asm/msr.h> +#include <asm/nmi.h> #include <asm/processor.h> #include <asm/setup.h> #include <asm/microcode.h> @@ -339,14 +340,8 @@ static int microcode_update_cpu(const struct microcode_patch *patch) static int slave_thread_fn(void) { - unsigned int cpu = smp_processor_id(); unsigned int master = cpumask_first(this_cpu(cpu_sibling_mask)); - while ( loading_state != LOADING_CALLIN ) - cpu_relax(); - - cpumask_set_cpu(cpu, &cpu_callin_map); - while ( loading_state != LOADING_EXIT ) cpu_relax(); @@ -399,6 +394,8 @@ static int control_thread_fn(const struct microcode_patch *patch) cpumask_set_cpu(cpu, &cpu_callin_map); + smp_send_nmi_allbutself(); + /* Waiting for all threads calling in */ ret = wait_for_condition(wait_cpu_callin, (void *)(unsigned long)num_online_cpus(), @@ -481,12 +478,28 @@ static int do_microcode_update(void *patch) return ret; } +static int microcode_nmi_callback(const struct cpu_user_regs *regs, int cpu) +{ + /* The first thread of a core is to load an update. Don't block it. */ + if ( cpu == cpumask_first(per_cpu(cpu_sibling_mask, cpu)) || + loading_state != LOADING_CALLIN ) + return 0; + + cpumask_set_cpu(cpu, &cpu_callin_map); + + while ( loading_state != LOADING_EXIT ) + cpu_relax(); + + return 0; +} + int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) buf, unsigned long len) { int ret; void *buffer; unsigned int cpu, updated; struct microcode_patch *patch; + nmi_callback_t *saved_nmi_callback; if ( len != (uint32_t)len ) return -E2BIG; @@ -551,6 +564,8 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) buf, unsigned long len) * watchdog timeout. */ watchdog_disable(); + + saved_nmi_callback = set_nmi_callback(microcode_nmi_callback); /* * Late loading dance. Why the heavy-handed stop_machine effort? * @@ -563,6 +578,7 @@ int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) buf, unsigned long len) * conservative and good. */ ret = stop_machine_run(do_microcode_update, patch, NR_CPUS); + set_nmi_callback(saved_nmi_callback); watchdog_enable(); updated = atomic_read(&cpu_updated); -- 1.8.3.1 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply index Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-19 1:25 [Xen-devel] [PATCH v9 00/15] improve late microcode loading Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 01/15] microcode/intel: extend microcode_update_match() Chao Gao 2019-08-28 15:12 ` Jan Beulich 2019-08-29 7:15 ` Chao Gao 2019-08-29 7:14 ` Jan Beulich 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 02/15] microcode/amd: fix memory leak Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 03/15] microcode/amd: distinguish old and mismatched ucode in microcode_fits() Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 04/15] microcode: introduce a global cache of ucode patch Chao Gao 2019-08-22 11:11 ` Roger Pau Monné 2019-08-28 15:21 ` Jan Beulich 2019-08-29 10:18 ` Jan Beulich 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 05/15] microcode: clean up microcode_resume_cpu Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 06/15] microcode: remove struct ucode_cpu_info Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 07/15] microcode: remove pointless 'cpu' parameter Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 08/15] microcode/amd: call svm_host_osvw_init() in common code Chao Gao 2019-08-22 13:08 ` Roger Pau Monné 2019-08-28 15:26 ` Jan Beulich 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 09/15] microcode: pass a patch pointer to apply_microcode() Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 10/15] microcode: split out apply_microcode() from cpu_request_microcode() Chao Gao 2019-08-22 13:59 ` Roger Pau Monné 2019-08-29 10:06 ` Jan Beulich 2019-08-30 3:22 ` Chao Gao 2019-08-30 7:25 ` Jan Beulich 2019-08-29 10:19 ` Jan Beulich 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 11/15] microcode: unify loading update during CPU resuming and AP wakeup Chao Gao 2019-08-22 14:10 ` Roger Pau Monné 2019-08-22 16:44 ` Chao Gao 2019-08-23 9:09 ` Roger Pau Monné 2019-08-29 7:37 ` Chao Gao 2019-08-29 8:16 ` Roger Pau Monné 2019-08-29 10:26 ` Jan Beulich 2019-08-29 10:29 ` Jan Beulich 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 12/15] microcode: reduce memory allocation and copy when creating a patch Chao Gao 2019-08-23 8:11 ` Roger Pau Monné 2019-08-26 7:03 ` Chao Gao 2019-08-26 8:11 ` Roger Pau Monné 2019-08-29 10:47 ` Jan Beulich 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 13/15] x86/microcode: Synchronize late microcode loading Chao Gao 2019-08-19 10:27 ` Sergey Dyasli 2019-08-19 14:49 ` Chao Gao 2019-08-29 12:06 ` Jan Beulich 2019-08-30 3:30 ` Chao Gao 2019-08-19 1:25 ` [Xen-devel] [PATCH v9 14/15] microcode: remove microcode_update_lock Chao Gao 2019-08-19 1:25 ` Chao Gao [this message] 2019-08-23 8:46 ` [Xen-devel] [PATCH v9 15/15] microcode: block #NMI handling when loading an ucode Sergey Dyasli 2019-08-26 8:07 ` Chao Gao 2019-08-27 4:52 ` Chao Gao 2019-08-28 8:52 ` Sergey Dyasli 2019-08-29 12:11 ` Jan Beulich 2019-08-30 6:35 ` Chao Gao 2019-09-09 5:52 ` Chao Gao 2019-09-09 6:16 ` Jan Beulich 2019-08-29 12:22 ` Jan Beulich 2019-08-30 6:33 ` Chao Gao 2019-08-30 7:30 ` Jan Beulich 2019-08-22 7:51 ` [Xen-devel] [PATCH v9 00/15] improve late microcode loading Sergey Dyasli 2019-08-22 15:39 ` Chao Gao
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