[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Re: [PATCH 1/5] xen: events: use irq_alloc_desc(_at) instead of open-coding an IRQ allocator.
On Tue, 26 Oct 2010, Ian Campbell wrote: > On Mon, 2010-10-25 at 19:02 +0100, Ian Campbell wrote: > > > > > > > What do you see when you pass in a PCI device and say give the guest > > 32 CPUs?? > > > > I can try tomorrow and see, based on what you say above without > > implementing what I described I suspect the answer will be "carnage". > > Actually, it looks like multi-vcpu is broken, I only see 1 regardless of > how many I configured. It's not clear if this is breakage in Linus' > tree, something I pulled in from one of Jeremy's, yours or Stefano's > trees or some local pebcak. I'll investigate... I found the bug, it was introduced by: "xen: use vcpu_ops to setup cpu masks" I have added the fix at the end of my branch and I am also appending the fix here. --- xen: initialize cpu masks for pv guests in xen_smp_init Pv guests don't have ACPI and need the cpu masks to be set correctly as early as possible so we call xen_fill_possible_map from xen_smp_init. On the other hand the initial domain supports ACPI so in this case we skip xen_fill_possible_map and rely on it. However Xen might limit the number of cpus usable by the domain, so we filter those masks during smp initialization using the VCPUOP_is_up hypercall. It is important that the filtering is done before xen_setup_vcpu_info_placement. Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 1386767..834dfeb 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -28,6 +28,7 @@ #include <asm/xen/interface.h> #include <asm/xen/hypercall.h> +#include <xen/xen.h> #include <xen/page.h> #include <xen/events.h> @@ -156,6 +157,25 @@ static void __init xen_fill_possible_map(void) { int i, rc; + if (xen_initial_domain()) + return; + + for (i = 0; i < nr_cpu_ids; i++) { + rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL); + if (rc >= 0) { + num_processors++; + set_cpu_possible(i, true); + } + } +} + +static void __init xen_filter_cpu_maps(void) +{ + int i, rc; + + if (!xen_initial_domain()) + return; + num_processors = 0; disabled_cpus = 0; for (i = 0; i < nr_cpu_ids; i++) { @@ -179,6 +199,7 @@ static void __init xen_smp_prepare_boot_cpu(void) old memory can be recycled */ make_lowmem_page_readwrite(xen_initial_gdt); + xen_filter_cpu_maps(); xen_setup_vcpu_info_placement(); } @@ -195,8 +216,6 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus) if (xen_smp_intr_init(0)) BUG(); - xen_fill_possible_map(); - if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL)) panic("could not allocate xen_cpu_initialized_map\n"); @@ -487,5 +506,6 @@ static const struct smp_ops xen_smp_ops __initdata = { void __init xen_smp_init(void) { smp_ops = xen_smp_ops; + xen_fill_possible_map(); xen_init_spinlocks(); } _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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