Attachment 897931 Details for Bug 1099599 – proposed fix (RHEL-6.6, RHEL-6.5.z)

[patch] proposed fix (RHEL-6.6, RHEL-6.5.z)

0001-CPU-hotplug-use-apic_id_for_cpu-round-2-RHEL-6-only.patch (text/plain), 2.44 KB, created by Laszlo Ersek on 2014-05-21 11:40:02 UTC

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Creator: Laszlo Ersek

Created: 2014-05-21 11:40:02 UTC

Size: 2.44 KB

patch

obsolete

>From 90ebbc3ee7502161ebf08052beacda5dd4e1a892 Mon Sep 17 00:00:00 2001
>From: Laszlo Ersek <lersek@redhat.com>
>Date: Wed, 21 May 2014 11:55:09 +0200
>Subject: [RHEL-6.6 qemu-kvm PATCH] CPU hotplug: use apic_id_for_cpu(), round 2
> (RHEL-6 only)
>
>In RHEL-6 commit 3685bf4b ("CPU hotplug: use apic_id_for_cpu()") we forgot
>to update the initialization of the gpe_regs.cpus_sts bitmap: the
>initializtion stayed in the VCPU index domain.
>
>This problem has remained unnoticed for quite some time, but recent RHEL-6
>commit 97c168a5 ("ACPI-level VCPU enablement info for libvirt (RHEL-6
>only)") has exposed it to libvirt as follows.
>
>Since 97c168a5, the "query-cpus" monitor command returns the
>"enabled-in-acpi" field too. Given that "enabled-in-acpi" keys off APIC
>IDs (correctly), but the underlying gpe_regs.cpus_sts bitmap is
>(incorrectly) initialized from VCPU indices, "query-cpus" reports some
>offline VCPUs right after initialization (for non-contiguous VCPU
>topologies), tripping up libvirt.
>
>Fix it by extending 3685bf4b to the init code.
>
>The change has no effect on machine types up to and including rhel6.3.0;
>apic_id_for_cpu() returns "cpu_index" transparently if
>"compat_contiguous_apic_ids" is set -- and that compat flag is set in
>pc_rhel630_compat().
>
>The change affects machine types rhel6.4.0 and rhel6.5.0 retroactively,
>which is arguably the right thing to do.
>
>Upstream status: n/a, same as for 3685bf4b and 97c168a5.
>
>Signed-off-by: Laszlo Ersek <lersek@redhat.com>
>---
> hw/acpi.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
>diff --git a/hw/acpi.c b/hw/acpi.c
>index 97adc12..347dc1f 100644
>--- a/hw/acpi.c
>+++ b/hw/acpi.c
>@@ -911,13 +911,19 @@ static int piix4_device_hotplug(PCIDevice *dev, int state);
> 
> void piix4_acpi_system_hot_add_init(PCIBus *bus, const char *cpu_model)
> {
>-    int i = 0, cpus = smp_cpus;
>+    int cpu_index;
>     struct gpe_regs *gpe = &pm_state->gpe;
> 
>-    while (cpus > 0) {
>-        gpe->cpus_sts[i++] = (cpus < 8) ? (1 << cpus) - 1 : 0xff;
>-        cpus -= 8;
>+    memset(gpe->cpus_sts, 0, sizeof gpe->cpus_sts);
>+    for (cpu_index = 0; cpu_index < smp_cpus; ++cpu_index) {
>+        uint32_t apic_id;
>+
>+        apic_id = apic_id_for_cpu(cpu_index);
>+        if (apic_id < sizeof gpe->cpus_sts * 8) {
>+            gpe->cpus_sts[apic_id / 8] |= (1 << (apic_id % 8));
>+        }
>     }
>+
>     register_ioport_write(GPE_BASE, 4, 1, gpe_writeb, gpe);
>     register_ioport_read(GPE_BASE, 4, 1,  gpe_readb, gpe);
> 
>-- 
>1.8.3.1
>

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Attachments on bug 1099599: 897931