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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen stable-4.6] x86: possibly bring up all CPUs even if not all are supposed to be used
commit 91cf29f7c680f399382ef50b422c1eb0a92a5b2e
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Jul 30 14:20:22 2018 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jul 30 14:20:22 2018 +0200
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 <jbeulich@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
master commit: 8797d20a6ec2dd75195585a107ce345c51c0a59a
master date: 2018-07-19 13:43:33 +0100
---
xen/arch/x86/cpu/common.c | 4 ++++
xen/arch/x86/cpu/mcheck/mce_intel.c | 2 --
xen/arch/x86/mpparse.c | 15 +++++++++++----
xen/arch/x86/setup.c | 18 +++++++++++++++---
xen/include/asm-x86/processor.h | 6 ------
5 files changed, 30 insertions(+), 15 deletions(-)
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 1fb8f1b5d8..7d1c32e335 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -15,6 +15,7 @@
#include <public/sysctl.h> /* for XEN_INVALID_{SOCKET,CORE}_ID */
#include "cpu.h"
+#include "mcheck/x86_mca.h"
static bool_t __cpuinitdata use_xsave = 1;
boolean_param("xsave", use_xsave);
@@ -209,6 +210,9 @@ static void __init early_cpu_detect(void)
c->x86_capability[0] = cap0;
c->x86_capability[4] = cap4;
+ if (c->x86_vendor != X86_VENDOR_AMD)
+ park_offline_cpus = !mce_disabled;
+
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 193366b002..a8afb9ba2d 100644
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c
@@ -628,8 +628,6 @@ static void clear_cmci(void)
static void cpu_mcheck_disable(void)
{
- clear_in_cr4(X86_CR4_MCE);
-
if (cmci_support && !mce_disabled)
clear_cmci();
}
diff --git a/xen/arch/x86/mpparse.c b/xen/arch/x86/mpparse.c
index 837ede96d3..c834ce30cb 100644
--- a/xen/arch/x86/mpparse.c
+++ b/xen/arch/x86/mpparse.c
@@ -69,19 +69,26 @@ 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 8adba9d19c..58ac554f39 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -616,7 +616,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
{
char *memmap_type = NULL;
char *cmdline, *kextra, *loader;
- unsigned int initrdidx, domcr_flags = DOMCRF_s3_integrity;
+ unsigned int initrdidx, num_parked = 0, domcr_flags = DOMCRF_s3_integrity;
multiboot_info_t *mbi = __va(mbi_p);
module_t *mod = (module_t *)__va(mbi->mods_addr);
unsigned long nr_pages, raw_max_page, modules_headroom, *module_map;
@@ -1319,7 +1319,8 @@ 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;
}
/* Low mappings were only needed for some BIOS table parsing. */
@@ -1431,15 +1432,26 @@ 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 ca535bb22b..02d5118c78 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -390,12 +390,6 @@ 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);
-}
-
/*
* NSC/Cyrix CPU configuration register indexes
*/
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6
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