|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 2/4] 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>
---
v2: Use ROUNDUP().
---
Instead of fully bringing up CPUs and then calling cpu_down(), another
option would be to suppress/cancel full bringup in smp_callin(). But I
guess we should try to keep things simple for now, and see later whether
this can be "optimized".
---
Note: The parked CPUs can be brought online (i.e. the meaning of
"maxcpus=" isn't as strict anymore as it was before), but won't
immediately be used for scheduling pre-existing Dom0 CPUs. That's
because dom0_setup_vcpu() artifically restricts the affinity. For
DomU-s whose affinity was not artifically restricted, no such
limitation exists, albeit the shown "soft" affinity appears to
suffer a similar issue. As that's not a goal of this patch, I've
put the issues on the side for now, perhaps for someone else to
take care of.
Note: On one of my test systems the parked CPUs get _PSD data reported
by Dom0 that is different from the non-parked ones (coord_type is
0xFC instead of 0xFE). Giving Dom0 enough vCPU-s eliminates this
problem, so there is apparently something amiss in the processor
driver. I've tried to figure out what, but I couldn't, despite the
AML suggesting that this might be some _OSC invocation (but if it
is, I can't find it - acpi_run_osc() clearly does not anywhere get
invoked in a per-CPU fashion).
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -13,6 +13,7 @@
#include <public/sysctl.h> /* for XEN_INVALID_{SOCKET,CORE}_ID */
#include "cpu.h"
+#include "mcheck/x86_mca.h"
bool_t opt_arat = 1;
boolean_param("arat", opt_arat);
@@ -343,6 +344,9 @@ 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);
}
--- 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();
}
--- 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
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -665,7 +665,7 @@ void __init noreturn __start_xen(unsigne
{
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;
@@ -1512,7 +1512,8 @@ void __init noreturn __start_xen(unsigne
else
{
set_nr_cpu_ids(max_cpus);
- max_cpus = nr_cpu_ids;
+ if ( !max_cpus )
+ max_cpus = nr_cpu_ids;
}
if ( xen_guest )
@@ -1635,16 +1636,27 @@ void __init noreturn __start_xen(unsigne
/* 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();
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -342,12 +342,6 @@ static always_inline void set_in_cr4 (un
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;
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |