| Message ID | 1361505524-18832-1-git-send-email-akorolex@gmail.com |
|---|---|
| State | New |
| Headers | show |
On 22 February 2013 03:58, Alexey Korolev <akorolex@gmail.com> wrote: > 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 <akorolex@gmail.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> as far as the sysbus changes go. I can't comment on whether the change to the PC emulation is correct or not but it looks vaguely plausible. thanks -- PMM
On 2013-02-22 04:58, Alexey Korolev wrote: > 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). So the issue it that we hide the MSI target region from the device models for a "short periods of time"? How short is this? It would be good to fully understand what goes "completely wrong" to avoid that we miss to fix something else (IO-APIC, HPET) or even paper over a problem of the memory subsystem. > > 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 <akorolex@gmail.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > 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 6d9d1df..50c7232 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 { Coding style: "} 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 a7fcded..2100bd7 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 dfcf86e..4cf27eb 100644 > --- a/target-i386/cpu.c > +++ b/target-i386/cpu.c > @@ -2078,7 +2078,8 @@ 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); ^^^^^^ Minor, but "0x" makes this look like an address. > apic_mapped = 1; > } > } > Jan
On Fri, Feb 22, 2013 at 04:58:44PM +1300, Alexey Korolev wrote: > 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 <akorolex@gmail.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> I agree we need to look closer at the modeling, but this looks like the right thing to do for 1.4 stable branch. So let's take it. Acked-by: Michael S. Tsirkin <mst@redhat.com> > --- > 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 6d9d1df..50c7232 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 a7fcded..2100bd7 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 dfcf86e..4cf27eb 100644 > --- a/target-i386/cpu.c > +++ b/target-i386/cpu.c > @@ -2078,7 +2078,8 @@ 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; > } > } > -- > 1.7.9.5
diff --git a/hw/sysbus.c b/hw/sysbus.c index 6d9d1df..50c7232 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 a7fcded..2100bd7 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 dfcf86e..4cf27eb 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -2078,7 +2078,8 @@ 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; } }