From: Jan Beulich Date: Mon, 30 Jul 2018 09:25:38 +0000 (+0200) Subject: x86: possibly bring up all CPUs even if not all are supposed to be used X-Git-Tag: RELEASE-4.11.1~72 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=75313e478e894176056e1fc5852136b344a0dc70;p=people%2Fdwmw2%2Fxen.git x86: possibly bring up all CPUs even if not all are supposed to be used Reportedly Intel CPUs which can't broadcast #MC to all targeted cores/threads because some have CR4.MCE clear will shut down. Therefore we want to keep CR4.MCE enabled when offlining a CPU, and we need to bring up all CPUs in order to be able to set CR4.MCE in the first place. The use of clear_in_cr4() in cpu_mcheck_disable() was ill advised anyway, and to avoid future similar mistakes I'm removing clear_in_cr4() altogether right here. Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper Reviewed-by: Roger Pau Monné Reviewed-by: Wei Liu master commit: 8797d20a6ec2dd75195585a107ce345c51c0a59a master date: 2018-07-19 13:43:33 +0100 --- diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c index 528aff1811..fdb022875a 100644 --- a/xen/arch/x86/cpu/common.c +++ b/xen/arch/x86/cpu/common.c @@ -14,6 +14,7 @@ #include /* for XEN_INVALID_{SOCKET,CORE}_ID */ #include "cpu.h" +#include "mcheck/x86_mca.h" bool_t opt_arat = 1; boolean_param("arat", opt_arat); @@ -355,6 +356,9 @@ static void __init early_cpu_detect(void) hap_paddr_bits = PADDR_BITS; } + if (c->x86_vendor != X86_VENDOR_AMD) + park_offline_cpus = opt_mce; + initialize_cpu_data(0); } diff --git a/xen/arch/x86/cpu/mcheck/mce_intel.c b/xen/arch/x86/cpu/mcheck/mce_intel.c index e5dd956a24..4474a34e34 100644 --- a/xen/arch/x86/cpu/mcheck/mce_intel.c +++ b/xen/arch/x86/cpu/mcheck/mce_intel.c @@ -636,8 +636,6 @@ static void clear_cmci(void) static void cpu_mcheck_disable(void) { - clear_in_cr4(X86_CR4_MCE); - if ( cmci_support && opt_mce ) clear_cmci(); } diff --git a/xen/arch/x86/mpparse.c b/xen/arch/x86/mpparse.c index 49140e46f0..f3f6d48668 100644 --- a/xen/arch/x86/mpparse.c +++ b/xen/arch/x86/mpparse.c @@ -68,19 +68,26 @@ physid_mask_t phys_cpu_present_map; void __init set_nr_cpu_ids(unsigned int max_cpus) { + unsigned int tot_cpus = num_processors + disabled_cpus; + if (!max_cpus) - max_cpus = num_processors + disabled_cpus; + max_cpus = tot_cpus; if (max_cpus > NR_CPUS) max_cpus = NR_CPUS; else if (!max_cpus) max_cpus = 1; printk(XENLOG_INFO "SMP: Allowing %u CPUs (%d hotplug CPUs)\n", max_cpus, max_t(int, max_cpus - num_processors, 0)); - nr_cpu_ids = max_cpus; + + if (!park_offline_cpus) + tot_cpus = max_cpus; + nr_cpu_ids = min(tot_cpus, NR_CPUS + 0u); + if (park_offline_cpus && nr_cpu_ids < num_processors) + printk(XENLOG_WARNING "SMP: Cannot bring up %u further CPUs\n", + num_processors - nr_cpu_ids); #ifndef nr_cpumask_bits - nr_cpumask_bits = (max_cpus + (BITS_PER_LONG - 1)) & - ~(BITS_PER_LONG - 1); + nr_cpumask_bits = ROUNDUP(nr_cpu_ids, BITS_PER_LONG); printk(XENLOG_DEBUG "NR_CPUS:%u nr_cpumask_bits:%u\n", NR_CPUS, nr_cpumask_bits); #endif diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index a3172ca92c..984c948216 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -665,7 +665,7 @@ void __init noreturn __start_xen(unsigned long mbi_p) { char *memmap_type = NULL; char *cmdline, *kextra, *loader; - unsigned int initrdidx; + unsigned int initrdidx, num_parked = 0; multiboot_info_t *mbi; module_t *mod; unsigned long nr_pages, raw_max_page, modules_headroom, *module_map; @@ -1494,7 +1494,8 @@ void __init noreturn __start_xen(unsigned long mbi_p) else { set_nr_cpu_ids(max_cpus); - max_cpus = nr_cpu_ids; + if ( !max_cpus ) + max_cpus = nr_cpu_ids; } if ( xen_guest ) @@ -1617,16 +1618,27 @@ void __init noreturn __start_xen(unsigned long mbi_p) /* Set up node_to_cpumask based on cpu_to_node[]. */ numa_add_cpu(i); - if ( (num_online_cpus() < max_cpus) && !cpu_online(i) ) + if ( (park_offline_cpus || num_online_cpus() < max_cpus) && + !cpu_online(i) ) { int ret = cpu_up(i); if ( ret != 0 ) printk("Failed to bring up CPU %u (error %d)\n", i, ret); + else if ( num_online_cpus() > max_cpus ) + { + ret = cpu_down(i); + if ( !ret ) + ++num_parked; + else + printk("Could not re-offline CPU%u (%d)\n", i, ret); + } } } } printk("Brought up %ld CPUs\n", (long)num_online_cpus()); + if ( num_parked ) + printk(XENLOG_INFO "Parked %u CPUs\n", num_parked); smp_cpus_done(); do_initcalls(); diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h index 9924cdf1f3..2bd9e69684 100644 --- a/xen/include/asm-x86/processor.h +++ b/xen/include/asm-x86/processor.h @@ -337,12 +337,6 @@ static always_inline void set_in_cr4 (unsigned long mask) write_cr4(read_cr4() | mask); } -static always_inline void clear_in_cr4 (unsigned long mask) -{ - mmu_cr4_features &= ~mask; - write_cr4(read_cr4() & ~mask); -} - static inline unsigned int read_pkru(void) { unsigned int pkru;