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>
1 file changed
