From 7feb640cf32d86f91f5a624136345eb6a63eab42 Mon Sep 17 00:00:00 2001 From: Alexey Korolev Date: Fri, 22 Feb 2013 16:58:44 +1300 Subject: [PATCH] Fix guest OS hang when 64bit PCI bar present This patch addresses the issue fully described here: http://lists.nongnu.org/archive/html/qemu-devel/2013-02/msg01804.html Linux kernels prior to 2.6.36 do not disable the PCI device during enumeration process. Since lower and higher parts of a 64bit BAR are programmed separately this leads to qemu receiving a request to occupy a completely wrong address region for a short period of time. We have found that the boot process screws up completely if kvm-apic range is overlapped even for a short period of time (it is fine for other regions though). This patch raises the priority of the kvm-apic memory region, so it is never pushed out by PCI devices. The patch is quite safe as it does not touch memory manager. Signed-off-by: Alexey Korolev Signed-off-by: Michael S. Tsirkin --- hw/sysbus.c | 27 +++++++++++++++++++++++---- hw/sysbus.h | 2 ++ target-i386/cpu.c | 3 ++- 3 files changed, 27 insertions(+), 5 deletions(-) diff --git a/hw/sysbus.c b/hw/sysbus.c index 6d9d1df419..50c7232799 100644 --- a/hw/sysbus.c +++ b/hw/sysbus.c @@ -48,7 +48,8 @@ void sysbus_connect_irq(SysBusDevice *dev, int n, qemu_irq irq) } } -void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr) +static void sysbus_mmio_map_common(SysBusDevice *dev, int n, hwaddr addr, + bool may_overlap, unsigned priority) { assert(n >= 0 && n < dev->num_mmio); @@ -61,11 +62,29 @@ void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr) memory_region_del_subregion(get_system_memory(), dev->mmio[n].memory); } dev->mmio[n].addr = addr; - memory_region_add_subregion(get_system_memory(), - addr, - dev->mmio[n].memory); + if (may_overlap) { + memory_region_add_subregion_overlap(get_system_memory(), + addr, + dev->mmio[n].memory, + priority); + } + else { + memory_region_add_subregion(get_system_memory(), + addr, + dev->mmio[n].memory); + } } +void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr) +{ + sysbus_mmio_map_common(dev, n, addr, false, 0); +} + +void sysbus_mmio_map_overlap(SysBusDevice *dev, int n, hwaddr addr, + unsigned priority) +{ + sysbus_mmio_map_common(dev, n, addr, true, priority); +} /* Request an IRQ source. The actual IRQ object may be populated later. */ void sysbus_init_irq(SysBusDevice *dev, qemu_irq *p) diff --git a/hw/sysbus.h b/hw/sysbus.h index a7fcded6e7..2100bd7d07 100644 --- a/hw/sysbus.h +++ b/hw/sysbus.h @@ -56,6 +56,8 @@ void sysbus_init_ioports(SysBusDevice *dev, pio_addr_t ioport, pio_addr_t size); void sysbus_connect_irq(SysBusDevice *dev, int n, qemu_irq irq); void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr); +void sysbus_mmio_map_overlap(SysBusDevice *dev, int n, hwaddr addr, + unsigned priority); void sysbus_add_memory(SysBusDevice *dev, hwaddr addr, MemoryRegion *mem); void sysbus_add_memory_overlap(SysBusDevice *dev, hwaddr addr, diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 5582e5f4e6..8fb736a5b4 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -2088,7 +2088,8 @@ static void x86_cpu_apic_init(X86CPU *cpu, Error **errp) /* NOTE: the APIC is directly connected to the CPU - it is not on the global memory bus. */ /* XXX: what if the base changes? */ - sysbus_mmio_map(SYS_BUS_DEVICE(env->apic_state), 0, MSI_ADDR_BASE); + sysbus_mmio_map_overlap(SYS_BUS_DEVICE(env->apic_state), 0, + MSI_ADDR_BASE, 0x1000); apic_mapped = 1; } } -- 2.11.0