From 3f1f576a195aa266813cbd4ca70291deb61e0129 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Fri, 16 Feb 2018 12:26:38 +0100 Subject: x86/microcode: Propagate return value from updating functions ... so that callers can know when microcode was updated and act accordingly. Tested-by: Ashok Raj Signed-off-by: Borislav Petkov Reviewed-by: Ashok Raj Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20180216112640.11554-2-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/microcode/amd.c | 10 +++++----- arch/x86/kernel/cpu/microcode/core.c | 33 +++++++++++++++++---------------- arch/x86/kernel/cpu/microcode/intel.c | 10 +++++----- 3 files changed, 27 insertions(+), 26 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 330b8462d426..a998e1a7d46f 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -498,7 +498,7 @@ static unsigned int verify_patch_size(u8 family, u32 patch_size, return patch_size; } -static int apply_microcode_amd(int cpu) +static enum ucode_state apply_microcode_amd(int cpu) { struct cpuinfo_x86 *c = &cpu_data(cpu); struct microcode_amd *mc_amd; @@ -512,7 +512,7 @@ static int apply_microcode_amd(int cpu) p = find_patch(cpu); if (!p) - return 0; + return UCODE_NFOUND; mc_amd = p->data; uci->mc = p->data; @@ -523,13 +523,13 @@ static int apply_microcode_amd(int cpu) if (rev >= mc_amd->hdr.patch_id) { c->microcode = rev; uci->cpu_sig.rev = rev; - return 0; + return UCODE_OK; } if (__apply_microcode_amd(mc_amd)) { pr_err("CPU%d: update failed for patch_level=0x%08x\n", cpu, mc_amd->hdr.patch_id); - return -1; + return UCODE_ERROR; } pr_info("CPU%d: new patch_level=0x%08x\n", cpu, mc_amd->hdr.patch_id); @@ -537,7 +537,7 @@ static int apply_microcode_amd(int cpu) uci->cpu_sig.rev = mc_amd->hdr.patch_id; c->microcode = mc_amd->hdr.patch_id; - return 0; + return UCODE_UPDATED; } static int install_equiv_cpu_table(const u8 *buf) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 319dd65f98a2..6fdaf7cf3182 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -374,7 +374,7 @@ static int collect_cpu_info(int cpu) } struct apply_microcode_ctx { - int err; + enum ucode_state err; }; static void apply_microcode_local(void *arg) @@ -489,31 +489,29 @@ static void __exit microcode_dev_exit(void) /* fake device for request_firmware */ static struct platform_device *microcode_pdev; -static int reload_for_cpu(int cpu) +static enum ucode_state reload_for_cpu(int cpu) { struct ucode_cpu_info *uci = ucode_cpu_info + cpu; enum ucode_state ustate; - int err = 0; if (!uci->valid) - return err; + return UCODE_OK; ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, true); - if (ustate == UCODE_OK) - apply_microcode_on_target(cpu); - else - if (ustate == UCODE_ERROR) - err = -EINVAL; - return err; + if (ustate != UCODE_OK) + return ustate; + + return apply_microcode_on_target(cpu); } static ssize_t reload_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { + enum ucode_state tmp_ret = UCODE_OK; unsigned long val; + ssize_t ret = 0; int cpu; - ssize_t ret = 0, tmp_ret; ret = kstrtoul(buf, 0, &val); if (ret) @@ -526,15 +524,18 @@ static ssize_t reload_store(struct device *dev, mutex_lock(µcode_mutex); for_each_online_cpu(cpu) { tmp_ret = reload_for_cpu(cpu); - if (tmp_ret != 0) + if (tmp_ret > UCODE_NFOUND) { pr_warn("Error reloading microcode on CPU %d\n", cpu); - /* save retval of the first encountered reload error */ - if (!ret) - ret = tmp_ret; + /* set retval for the first encountered reload error */ + if (!ret) + ret = -EINVAL; + } } - if (!ret) + + if (!ret && tmp_ret == UCODE_UPDATED) perf_check_microcode(); + mutex_unlock(µcode_mutex); put_online_cpus(); diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index a15db2b4e0d6..923054a6b760 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -772,7 +772,7 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig) return 0; } -static int apply_microcode_intel(int cpu) +static enum ucode_state apply_microcode_intel(int cpu) { struct microcode_intel *mc; struct ucode_cpu_info *uci; @@ -782,7 +782,7 @@ static int apply_microcode_intel(int cpu) /* We should bind the task to the CPU */ if (WARN_ON(raw_smp_processor_id() != cpu)) - return -1; + return UCODE_ERROR; uci = ucode_cpu_info + cpu; mc = uci->mc; @@ -790,7 +790,7 @@ static int apply_microcode_intel(int cpu) /* Look for a newer patch in our cache: */ mc = find_patch(uci); if (!mc) - return 0; + return UCODE_NFOUND; } /* write microcode via MSR 0x79 */ @@ -801,7 +801,7 @@ static int apply_microcode_intel(int cpu) if (rev != mc->hdr.rev) { pr_err("CPU%d update to revision 0x%x failed\n", cpu, mc->hdr.rev); - return -1; + return UCODE_ERROR; } if (rev != prev_rev) { @@ -818,7 +818,7 @@ static int apply_microcode_intel(int cpu) uci->cpu_sig.rev = rev; c->microcode = rev; - return 0; + return UCODE_UPDATED; } static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size, -- cgit v1.2.3 From 1008c52c09dcb23d93f8e0ea83a6246265d2cce0 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Fri, 16 Feb 2018 12:26:39 +0100 Subject: x86/CPU: Add a microcode loader callback Add a callback function which the microcode loader calls when microcode has been updated to a newer revision. Do the callback only when no error was encountered during loading. Tested-by: Ashok Raj Signed-off-by: Borislav Petkov Reviewed-by: Ashok Raj Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20180216112640.11554-3-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/include/asm/processor.h | 1 + arch/x86/kernel/cpu/common.c | 10 ++++++++++ arch/x86/kernel/cpu/microcode/core.c | 8 ++++++-- 3 files changed, 17 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 1bd9ed87606f..b0ccd4847a58 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -977,4 +977,5 @@ bool xen_set_default_idle(void); void stop_this_cpu(void *dummy); void df_debug(struct pt_regs *regs, long error_code); +void microcode_check(void); #endif /* _ASM_X86_PROCESSOR_H */ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 824aee0117bb..84f1cd88608b 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1749,3 +1749,13 @@ static int __init init_cpu_syscore(void) return 0; } core_initcall(init_cpu_syscore); + +/* + * The microcode loader calls this upon late microcode load to recheck features, + * only when microcode has been updated. Caller holds microcode_mutex and CPU + * hotplug lock. + */ +void microcode_check(void) +{ + perf_check_microcode(); +} diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 6fdaf7cf3182..aa1b9a422f2b 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -509,6 +509,7 @@ static ssize_t reload_store(struct device *dev, const char *buf, size_t size) { enum ucode_state tmp_ret = UCODE_OK; + bool do_callback = false; unsigned long val; ssize_t ret = 0; int cpu; @@ -531,10 +532,13 @@ static ssize_t reload_store(struct device *dev, if (!ret) ret = -EINVAL; } + + if (tmp_ret == UCODE_UPDATED) + do_callback = true; } - if (!ret && tmp_ret == UCODE_UPDATED) - perf_check_microcode(); + if (!ret && do_callback) + microcode_check(); mutex_unlock(µcode_mutex); put_online_cpus(); -- cgit v1.2.3 From 854857f5944c59a881ff607b37ed9ed41d031a3b Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Wed, 28 Feb 2018 11:28:40 +0100 Subject: x86/microcode: Get rid of struct apply_microcode_ctx It is a useless remnant from earlier times. Use the ucode_state enum directly. No functional change. Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Tom Lendacky Tested-by: Ashok Raj Cc: Arjan Van De Ven Link: https://lkml.kernel.org/r/20180228102846.13447-2-bp@alien8.de --- arch/x86/kernel/cpu/microcode/core.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index aa1b9a422f2b..63370651e376 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -373,26 +373,23 @@ static int collect_cpu_info(int cpu) return ret; } -struct apply_microcode_ctx { - enum ucode_state err; -}; - static void apply_microcode_local(void *arg) { - struct apply_microcode_ctx *ctx = arg; + enum ucode_state *err = arg; - ctx->err = microcode_ops->apply_microcode(smp_processor_id()); + *err = microcode_ops->apply_microcode(smp_processor_id()); } static int apply_microcode_on_target(int cpu) { - struct apply_microcode_ctx ctx = { .err = 0 }; + enum ucode_state err; int ret; - ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1); - if (!ret) - ret = ctx.err; - + ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1); + if (!ret) { + if (err == UCODE_ERROR) + ret = 1; + } return ret; } -- cgit v1.2.3 From c182d2b7d0ca48e0d6ff16f7d883161238c447ed Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Wed, 28 Feb 2018 11:28:41 +0100 Subject: 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 Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Tom Lendacky Tested-by: Ashok Raj Cc: Arjan Van De Ven 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(-) (limited to 'arch/x86/kernel/cpu/microcode') 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; -- cgit v1.2.3 From 91df9fdf51492aec9fed6b4cbd33160886740f47 Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Wed, 28 Feb 2018 11:28:42 +0100 Subject: x86/microcode/intel: Writeback and invalidate caches before updating microcode Updating microcode is less error prone when caches have been flushed and depending on what exactly the microcode is updating. For example, some of the issues around certain Broadwell parts can be addressed by doing a full cache flush. [ Borislav: Massage it and use native_wbinvd() in both cases. ] Signed-off-by: Ashok Raj Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Tom Lendacky Tested-by: Ashok Raj Cc: Arjan Van De Ven Link: http://lkml.kernel.org/r/1519352533-15992-3-git-send-email-ashok.raj@intel.com Link: https://lkml.kernel.org/r/20180228102846.13447-4-bp@alien8.de --- arch/x86/kernel/cpu/microcode/intel.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index 87bd6dc94081..e2864bc2d575 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -600,6 +600,12 @@ static int apply_microcode_early(struct ucode_cpu_info *uci, bool early) return UCODE_OK; } + /* + * Writeback and invalidate caches before updating microcode to avoid + * internal issues depending on what the microcode is updating. + */ + native_wbinvd(); + /* write microcode via MSR 0x79 */ native_wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits); @@ -816,6 +822,12 @@ static enum ucode_state apply_microcode_intel(int cpu) return UCODE_OK; } + /* + * Writeback and invalidate caches before updating microcode to avoid + * internal issues depending on what the microcode is updating. + */ + native_wbinvd(); + /* write microcode via MSR 0x79 */ wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits); -- cgit v1.2.3 From 30ec26da9967d0d785abc24073129a34c3211777 Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Wed, 28 Feb 2018 11:28:43 +0100 Subject: x86/microcode: Do not upload microcode if CPUs are offline Avoid loading microcode if any of the CPUs are offline, and issue a warning. Having different microcode revisions on the system at any time is outright dangerous. [ Borislav: Massage changelog. ] Signed-off-by: Ashok Raj Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Tom Lendacky Tested-by: Ashok Raj Reviewed-by: Tom Lendacky Cc: Arjan Van De Ven Link: http://lkml.kernel.org/r/1519352533-15992-4-git-send-email-ashok.raj@intel.com Link: https://lkml.kernel.org/r/20180228102846.13447-5-bp@alien8.de --- arch/x86/kernel/cpu/microcode/core.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 63370651e376..fa32cb3dcca5 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -486,6 +486,16 @@ static void __exit microcode_dev_exit(void) /* fake device for request_firmware */ static struct platform_device *microcode_pdev; +static int check_online_cpus(void) +{ + if (num_online_cpus() == num_present_cpus()) + return 0; + + pr_err("Not all CPUs online, aborting microcode update.\n"); + + return -EINVAL; +} + static enum ucode_state reload_for_cpu(int cpu) { struct ucode_cpu_info *uci = ucode_cpu_info + cpu; @@ -519,7 +529,13 @@ static ssize_t reload_store(struct device *dev, return size; get_online_cpus(); + + ret = check_online_cpus(); + if (ret) + goto put; + mutex_lock(µcode_mutex); + for_each_online_cpu(cpu) { tmp_ret = reload_for_cpu(cpu); if (tmp_ret > UCODE_NFOUND) { @@ -538,6 +554,8 @@ static ssize_t reload_store(struct device *dev, microcode_check(); mutex_unlock(µcode_mutex); + +put: put_online_cpus(); if (!ret) -- cgit v1.2.3 From d8c3b52c00a05036e0a6b315b4b17921a7b67997 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Wed, 28 Feb 2018 11:28:44 +0100 Subject: x86/microcode/intel: Look into the patch cache first The cache might contain a newer patch - look in there first. A follow-on change will make sure newest patches are loaded into the cache of microcode patches. Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Tom Lendacky Tested-by: Ashok Raj Cc: Arjan Van De Ven Link: https://lkml.kernel.org/r/20180228102846.13447-6-bp@alien8.de --- arch/x86/kernel/cpu/microcode/intel.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index e2864bc2d575..2aded9db1d42 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -791,9 +791,9 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig) static enum ucode_state apply_microcode_intel(int cpu) { - struct microcode_intel *mc; - struct ucode_cpu_info *uci; + struct ucode_cpu_info *uci = ucode_cpu_info + cpu; struct cpuinfo_x86 *c = &cpu_data(cpu); + struct microcode_intel *mc; static int prev_rev; u32 rev; @@ -801,11 +801,10 @@ static enum ucode_state apply_microcode_intel(int cpu) if (WARN_ON(raw_smp_processor_id() != cpu)) return UCODE_ERROR; - uci = ucode_cpu_info + cpu; - mc = uci->mc; + /* Look for a newer patch in our cache: */ + mc = find_patch(uci); if (!mc) { - /* Look for a newer patch in our cache: */ - mc = find_patch(uci); + mc = uci->mc; if (!mc) return UCODE_NFOUND; } -- cgit v1.2.3 From cfb52a5a09c8ae3a1dafb44ce549fde5b69e8117 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Wed, 28 Feb 2018 11:28:45 +0100 Subject: x86/microcode: Request microcode on the BSP ... so that any newer version can land in the cache and can later be fished out by the application functions. Do that before grabbing the hotplug lock. Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Tom Lendacky Tested-by: Ashok Raj Reviewed-by: Tom Lendacky Cc: Arjan Van De Ven Link: https://lkml.kernel.org/r/20180228102846.13447-7-bp@alien8.de --- arch/x86/kernel/cpu/microcode/core.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index fa32cb3dcca5..5dd157d48606 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -499,15 +499,10 @@ static int check_online_cpus(void) static enum ucode_state reload_for_cpu(int cpu) { struct ucode_cpu_info *uci = ucode_cpu_info + cpu; - enum ucode_state ustate; if (!uci->valid) return UCODE_OK; - ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, true); - if (ustate != UCODE_OK) - return ustate; - return apply_microcode_on_target(cpu); } @@ -515,11 +510,11 @@ static ssize_t reload_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { + int cpu, bsp = boot_cpu_data.cpu_index; enum ucode_state tmp_ret = UCODE_OK; bool do_callback = false; unsigned long val; ssize_t ret = 0; - int cpu; ret = kstrtoul(buf, 0, &val); if (ret) @@ -528,6 +523,10 @@ static ssize_t reload_store(struct device *dev, if (val != 1) return size; + tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev, true); + if (tmp_ret != UCODE_OK) + return size; + get_online_cpus(); ret = check_online_cpus(); -- cgit v1.2.3 From a5321aec6412b20b5ad15db2d6b916c05349dbff Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Wed, 28 Feb 2018 11:28:46 +0100 Subject: x86/microcode: Synchronize late microcode loading Original idea by Ashok, completely rewritten by Borislav. Before you read any further: the early loading method is still the preferred one and you should always do that. The following patch is improving the late loading mechanism for long running jobs and cloud use cases. Gather all cores and serialize the microcode update on them by doing it one-by-one to make the late update process as reliable as possible and avoid potential issues caused by the microcode update. [ Borislav: Rewrite completely. ] Co-developed-by: Borislav Petkov Signed-off-by: Ashok Raj Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Tested-by: Tom Lendacky Tested-by: Ashok Raj Reviewed-by: Tom Lendacky Cc: Arjan Van De Ven Link: https://lkml.kernel.org/r/20180228102846.13447-8-bp@alien8.de --- arch/x86/kernel/cpu/microcode/core.c | 118 +++++++++++++++++++++++++++-------- 1 file changed, 92 insertions(+), 26 deletions(-) (limited to 'arch/x86/kernel/cpu/microcode') diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 5dd157d48606..70ecbc8099c9 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -22,13 +22,16 @@ #define pr_fmt(fmt) "microcode: " fmt #include +#include #include #include #include #include #include +#include #include #include +#include #include #include @@ -64,6 +67,11 @@ LIST_HEAD(microcode_cache); */ static DEFINE_MUTEX(microcode_mutex); +/* + * Serialize late loading so that CPUs get updated one-by-one. + */ +static DEFINE_SPINLOCK(update_lock); + struct ucode_cpu_info ucode_cpu_info[NR_CPUS]; struct cpu_info_ctx { @@ -486,6 +494,19 @@ static void __exit microcode_dev_exit(void) /* fake device for request_firmware */ static struct platform_device *microcode_pdev; +/* + * Late loading dance. Why the heavy-handed stomp_machine effort? + * + * - HT siblings must be idle and not execute other code while the other sibling + * is loading microcode in order to avoid any negative interactions caused by + * the loading. + * + * - In addition, microcode update on the cores must be serialized until this + * requirement can be relaxed in the future. Right now, this is conservative + * and good. + */ +#define SPINUNIT 100 /* 100 nsec */ + static int check_online_cpus(void) { if (num_online_cpus() == num_present_cpus()) @@ -496,23 +517,85 @@ static int check_online_cpus(void) return -EINVAL; } -static enum ucode_state reload_for_cpu(int cpu) +static atomic_t late_cpus; + +/* + * Returns: + * < 0 - on error + * 0 - no update done + * 1 - microcode was updated + */ +static int __reload_late(void *info) { - struct ucode_cpu_info *uci = ucode_cpu_info + cpu; + unsigned int timeout = NSEC_PER_SEC; + int all_cpus = num_online_cpus(); + int cpu = smp_processor_id(); + enum ucode_state err; + int ret = 0; - if (!uci->valid) - return UCODE_OK; + atomic_dec(&late_cpus); + + /* + * Wait for all CPUs to arrive. A load will not be attempted unless all + * CPUs show up. + * */ + while (atomic_read(&late_cpus)) { + if (timeout < SPINUNIT) { + pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n", + atomic_read(&late_cpus)); + return -1; + } + + ndelay(SPINUNIT); + timeout -= SPINUNIT; + + touch_nmi_watchdog(); + } + + spin_lock(&update_lock); + apply_microcode_local(&err); + spin_unlock(&update_lock); + + if (err > UCODE_NFOUND) { + pr_warn("Error reloading microcode on CPU %d\n", cpu); + ret = -1; + } else if (err == UCODE_UPDATED) { + ret = 1; + } - return apply_microcode_on_target(cpu); + atomic_inc(&late_cpus); + + while (atomic_read(&late_cpus) != all_cpus) + cpu_relax(); + + return ret; +} + +/* + * Reload microcode late on all CPUs. Wait for a sec until they + * all gather together. + */ +static int microcode_reload_late(void) +{ + int ret; + + atomic_set(&late_cpus, num_online_cpus()); + + ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask); + if (ret < 0) + return ret; + else if (ret > 0) + microcode_check(); + + return ret; } static ssize_t reload_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t size) { - int cpu, bsp = boot_cpu_data.cpu_index; enum ucode_state tmp_ret = UCODE_OK; - bool do_callback = false; + int bsp = boot_cpu_data.cpu_index; unsigned long val; ssize_t ret = 0; @@ -534,30 +617,13 @@ static ssize_t reload_store(struct device *dev, goto put; mutex_lock(µcode_mutex); - - for_each_online_cpu(cpu) { - tmp_ret = reload_for_cpu(cpu); - if (tmp_ret > UCODE_NFOUND) { - pr_warn("Error reloading microcode on CPU %d\n", cpu); - - /* set retval for the first encountered reload error */ - if (!ret) - ret = -EINVAL; - } - - if (tmp_ret == UCODE_UPDATED) - do_callback = true; - } - - if (!ret && do_callback) - microcode_check(); - + ret = microcode_reload_late(); mutex_unlock(µcode_mutex); put: put_online_cpus(); - if (!ret) + if (ret >= 0) ret = size; return ret; -- cgit v1.2.3