From cbd88c8e6f5cdb8d4b9af01df825305200240382 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 9 Mar 2009 10:06:22 -0600 Subject: lguest: fix crash 'unhandled trap 13 at ' Impact: fix lguest boot crash on modern Intel machines The code in early_init_intel does: if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { u64 misc_enable; rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); And that rdmsr faults (not allowed from non-0 PL). We can get around this by mugging the family ID part of the cpuid. 5 seems like a good number. Of course, this is a hack (how very lguest!). We could just indicate that we don't support MSRs, or implement lguest_rdmst. Reported-by: Patrick McHardy Signed-off-by: Rusty Russell Tested-by: Patrick McHardy --- arch/x86/lguest/boot.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 92f1c6f3e19..ba5c05e97f1 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -343,6 +343,11 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx, * flush_tlb_user() for both user and kernel mappings unless * the Page Global Enable (PGE) feature bit is set. */ *dx |= 0x00002000; + /* We also lie, and say we're family id 5. 6 or greater + * leads to a rdmsr in early_init_intel which we can't handle. + * Family ID is returned as bits 8-12 in ax. */ + *ax &= 0xFFFFF0FF; + *ax |= 0x00000500; break; case 0x80000000: /* Futureproof this a little: if they ask how much extended -- cgit v1.2.3-70-g09d2 From 6db6a5f3ae2ca6b874b0fd97ae16fdc9b5cdd6cc Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 9 Mar 2009 10:06:28 -0600 Subject: lguest: fix for CONFIG_SPARSE_IRQ=y Impact: remove lots of lguest boot WARN_ON() when CONFIG_SPARSE_IRQ=y We now need to call irq_to_desc_alloc_cpu() before set_irq_chip_and_handler_name(), but we can't do that from init_IRQ (no kmalloc available). So do it as we use interrupts instead. Also means we only alloc for irqs we use, which was the intent of CONFIG_SPARSE_IRQ anyway. Signed-off-by: Rusty Russell Cc: Ingo Molnar --- arch/x86/lguest/boot.c | 16 +++++++++------- drivers/lguest/lguest_device.c | 6 ++++++ 2 files changed, 15 insertions(+), 7 deletions(-) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index ba5c05e97f1..960a8d9c049 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -594,19 +594,21 @@ static void __init lguest_init_IRQ(void) /* Some systems map "vectors" to interrupts weirdly. Lguest has * a straightforward 1 to 1 mapping, so force that here. */ __get_cpu_var(vector_irq)[vector] = i; - if (vector != SYSCALL_VECTOR) { - set_intr_gate(vector, - interrupt[vector-FIRST_EXTERNAL_VECTOR]); - set_irq_chip_and_handler_name(i, &lguest_irq_controller, - handle_level_irq, - "level"); - } + if (vector != SYSCALL_VECTOR) + set_intr_gate(vector, interrupt[i]); } /* This call is required to set up for 4k stacks, where we have * separate stacks for hard and soft interrupts. */ irq_ctx_init(smp_processor_id()); } +void lguest_setup_irq(unsigned int irq) +{ + irq_to_desc_alloc_cpu(irq, 0); + set_irq_chip_and_handler_name(irq, &lguest_irq_controller, + handle_level_irq, "level"); +} + /* * Time. * diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c index b4d44e571d7..8132533d71f 100644 --- a/drivers/lguest/lguest_device.c +++ b/drivers/lguest/lguest_device.c @@ -212,6 +212,9 @@ static void lg_notify(struct virtqueue *vq) hcall(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT, 0, 0); } +/* An extern declaration inside a C file is bad form. Don't do it. */ +extern void lguest_setup_irq(unsigned int irq); + /* This routine finds the first virtqueue described in the configuration of * this device and sets it up. * @@ -266,6 +269,9 @@ static struct virtqueue *lg_find_vq(struct virtio_device *vdev, goto unmap; } + /* Make sure the interrupt is allocated. */ + lguest_setup_irq(lvq->config.irq); + /* Tell the interrupt for this virtqueue to go to the virtio_ring * interrupt handler. */ /* FIXME: We used to have a flag for the Host to tell us we could use -- cgit v1.2.3-70-g09d2