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| author | Alexandru Elisei <alexandru.elisei@arm.com> | 2020-05-14 16:38:29 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-19 17:38:02 +0100 |
| commit | b4fc4f605fc66a0942e88f37b3a4b18671e32b0c (patch) | |
| tree | aa93cdcea22f38716bdecfe0ff0d011877f6973c | |
| parent | ad5e9056de0cc37bf4b4632d61e64a4deca2c7a6 (diff) | |
| download | kvmtool-b4fc4f605fc66a0942e88f37b3a4b18671e32b0c.tar.gz | |
vfio: Trap MMIO access to BAR addresses which aren't page aligned
KVM_SET_USER_MEMORY_REGION will fail if the guest physical address is
not aligned to the page size. However, it is legal for a guest to
program an address which isn't aligned to the page size. Trap and
emulate MMIO accesses to the region when that happens.
Without this patch, when assigning a Seagate Barracude hard drive to a
VM I was seeing these errors:
[ 0.286029] pci 0000:00:00.0: BAR 0: assigned [mem 0x41004600-0x4100467f]
Error: 0000:01:00.0: failed to register region with KVM
Error: [1095:3132] Error activating emulation for BAR 0
[..]
[ 10.561794] irq 13: nobody cared (try booting with the "irqpoll" option)
[ 10.563122] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-seattle-00009-g909b20467ed1 #133
[ 10.563124] Hardware name: linux,dummy-virt (DT)
[ 10.563126] Call trace:
[ 10.563134] dump_backtrace+0x0/0x140
[ 10.563137] show_stack+0x14/0x20
[ 10.563141] dump_stack+0xbc/0x100
[ 10.563146] __report_bad_irq+0x48/0xd4
[ 10.563148] note_interrupt+0x288/0x378
[ 10.563151] handle_irq_event_percpu+0x80/0x88
[ 10.563153] handle_irq_event+0x44/0xc8
[ 10.563155] handle_fasteoi_irq+0xb4/0x160
[ 10.563157] generic_handle_irq+0x24/0x38
[ 10.563159] __handle_domain_irq+0x60/0xb8
[ 10.563162] gic_handle_irq+0x50/0xa0
[ 10.563164] el1_irq+0xb8/0x180
[ 10.563166] arch_cpu_idle+0x10/0x18
[ 10.563170] do_idle+0x204/0x290
[ 10.563172] cpu_startup_entry+0x20/0x40
[ 10.563175] rest_init+0xd4/0xe0
[ 10.563180] arch_call_rest_init+0xc/0x14
[ 10.563182] start_kernel+0x420/0x44c
[ 10.563183] handlers:
[ 10.563650] [<000000001e474803>] sil24_interrupt
[ 10.564559] Disabling IRQ #13
[..]
[ 11.832916] ata1: spurious interrupt (slot_stat 0x0 active_tag -84148995 sactive 0x0)
[ 12.045444] ata_ratelimit: 1 callbacks suppressed
With this patch, I don't see the errors and the device works as
expected.
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/1589470709-4104-13-git-send-email-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | vfio/core.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/vfio/core.c b/vfio/core.c index bad3c7c8..0b45e78b 100644 --- a/vfio/core.c +++ b/vfio/core.c @@ -226,6 +226,15 @@ int vfio_map_region(struct kvm *kvm, struct vfio_device *vdev, if (!(region->info.flags & VFIO_REGION_INFO_FLAG_MMAP)) return vfio_setup_trap_region(kvm, vdev, region); + /* + * KVM_SET_USER_MEMORY_REGION will fail because the guest physical + * address isn't page aligned, let's emulate the region ourselves. + */ + if (region->guest_phys_addr & (PAGE_SIZE - 1)) + return kvm__register_mmio(kvm, region->guest_phys_addr, + region->info.size, false, + vfio_mmio_access, region); + if (region->info.flags & VFIO_REGION_INFO_FLAG_READ) prot |= PROT_READ; if (region->info.flags & VFIO_REGION_INFO_FLAG_WRITE) |