Re: [Xen-devel] [PATCH v2] xen-apic: Enable on domU as well
From: Konrad Rzeszutek Wilk <hidden>
Date: 2015-08-07 14:23:40
Also in:
lkml, stable
On Thu, Aug 06, 2015 at 06:37:05PM +0200, Jason A. Donenfeld wrote:
It turns out that domU also requires the Xen APIC driver. Otherwise we
get stuck in busy loops that never exit, such as in this stack trace:
(gdb) target remote localhost:9999
Remote debugging using localhost:9999
__xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
56 while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
(gdb) bt
#0 __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
#1 __default_send_IPI_shortcut (shortcut=<optimized out>,
dest=<optimized out>, vector=<optimized out>) at
./arch/x86/include/asm/ipi.h:75
#2 apic_send_IPI_self (vector=246) at arch/x86/kernel/apic/probe_64.c:54
#3 0xffffffff81011336 in arch_irq_work_raise () at
arch/x86/kernel/irq_work.c:47
#4 0xffffffff8114990c in irq_work_queue (work=0xffff88000fc0e400) at
kernel/irq_work.c:100
#5 0xffffffff8110c29d in wake_up_klogd () at kernel/printk/printk.c:2633
#6 0xffffffff8110ca60 in vprintk_emit (facility=0, level=<optimized
out>, dict=0x0 <irq_stack_union>, dictlen=<optimized out>,
fmt=<optimized out>, args=<optimized out>)
at kernel/printk/printk.c:1778
#7 0xffffffff816010c8 in printk (fmt=<optimized out>) at
kernel/printk/printk.c:1868
#8 0xffffffffc00013ea in ?? ()
#9 0x0000000000000000 in ?? ()
Mailing-list-thread: https://lkml.org/lkml/2015/8/4/755
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: David Vrabel <redacted>
Cc: Ian Campbell <redacted>
Cc: <redacted>While this patch is OK for the trees that implement the PV APIC driver it won't apply to older ones (and it does not need to). In the older ones this was working with f447d56d36af18c5104ff29dcb1327c0c0ac3634 "xen: implement apic ipi interface", which should have worked for your case. And would have made the arch_irq_work_raise and such use the Xen code paths: 952 953 #ifdef CONFIG_SMP 954 apic->send_IPI_allbutself = xen_send_IPI_allbutself; 955 apic->send_IPI_mask_allbutself = xen_send_IPI_mask_allbutself; 956 apic->send_IPI_mask = xen_send_IPI_mask; 957 apic->send_IPI_all = xen_send_IPI_all; 958 apic->send_IPI_self = xen_send_IPI_self; 959 #endif Anyhow, your patch seems to fix a regression my patch feb44f1f7a4ac299d1ab1c3606860e70b9b89d69 "x86/xen: Provide a "Xen PV" APIC driver to support >255 VCPUs" introduced. I would to the stable.vger.kernel.org: # apply only to v4.1 As the earlier ones will work fine. Thank you! Oh, and Reviewed-by: Konrad Rzeszutek Wilk [off-list ref]
quoted hunk ↗ jump to hunk
--- arch/x86/xen/Makefile | 4 ++-- arch/x86/xen/xen-ops.h | 11 ++++------- 2 files changed, 6 insertions(+), 9 deletions(-)diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile index 7322755..4b6e29a 100644 --- a/arch/x86/xen/Makefile +++ b/arch/x86/xen/Makefile@@ -13,13 +13,13 @@ CFLAGS_mmu.o := $(nostackp) obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \ time.o xen-asm.o xen-asm_$(BITS).o \ grant-table.o suspend.o platform-pci-unplug.o \ - p2m.o + p2m.o apic.o obj-$(CONFIG_EVENT_TRACING) += trace.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o -obj-$(CONFIG_XEN_DOM0) += apic.o vga.o +obj-$(CONFIG_XEN_DOM0) += vga.o obj-$(CONFIG_SWIOTLB_XEN) += pci-swiotlb-xen.o obj-$(CONFIG_XEN_EFI) += efi.odiff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index c20fe29..cd248ff 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h@@ -98,20 +98,17 @@ static inline void xen_uninit_lock_cpu(int cpu) #endif struct dom0_vga_console_info; - #ifdef CONFIG_XEN_DOM0 void __init xen_init_vga(const struct dom0_vga_console_info *, size_t size); -void __init xen_init_apic(void); #else -static inline void __init xen_init_vga(const struct dom0_vga_console_info *info, - size_t size) -{ -} -static inline void __init xen_init_apic(void) +void __init xen_init_vga(const struct dom0_vga_console_info *info, + size_t size); { } #endif +void __init xen_init_apic(void); + #ifdef CONFIG_XEN_EFI extern void xen_efi_init(void); #else-- 2.5.0 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel