Take into account that sg->offset can be bigger than PAGE_SIZE when
setting segment sg->dma_address. Otherwise sg->dma_address will point
at diffrent page, what makes DMA not possible with erros like this:
xhci_hcd :38:00.3: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x
address=0xfdaa70c0 flags=0x0020]
xhci_hcd :38:00.3: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x
address=0xfdaa7040 flags=0x0020]
xhci_hcd :38:00.3: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x
address=0xfdaa7080 flags=0x0020]
xhci_hcd :38:00.3: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x
address=0xfdaa7100 flags=0x0020]
xhci_hcd :38:00.3: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x
address=0xfdaa7000 flags=0x0020]
Additinally with wrong sg->dma_address unmap_sg will free wrong pages,
what what can cause crashes like this:
Feb 28 19:27:45 kernel: BUG: Bad page state in process cinnamon pfn:39e8b1
Feb 28 19:27:45 kernel: Disabling lock debugging due to kernel taint
Feb 28 19:27:45 kernel: flags: 0x200()
Feb 28 19:27:45 kernel: raw: 0200 0301
Feb 28 19:27:45 kernel: raw: 0001
Feb 28 19:27:45 kernel: page dumped because: nonzero _refcount
Feb 28 19:27:45 kernel: Modules linked in: ccm fuse arc4 nct6775 hwmon_vid
amdgpu nls_iso8859_1 nls_cp437 edac_mce_amd vfat fat kvm_amd ccp rng_core kvm
mt76x0u mt76x0_common mt76x02_usb irqbypass mt76_usb mt76x02_lib mt76
crct10dif_pclmul crc32_pclmul chash mac80211 amd_iommu_v2 ghash_clmulni_intel
gpu_sched i2c_algo_bit ttm wmi_bmof snd_hda_codec_realtek snd_hda_codec_generic
drm_kms_helper snd_hda_codec_hdmi snd_hda_intel drm snd_hda_codec aesni_intel
snd_hda_core snd_hwdep aes_x86_64 crypto_simd snd_pcm cfg80211 cryptd mousedev
snd_timer glue_helper pcspkr r8169 input_leds realtek agpgart libphy rfkill snd
syscopyarea sysfillrect sysimgblt fb_sys_fops soundcore sp5100_tco k10temp
i2c_piix4 wmi evdev gpio_amdpt pinctrl_amd mac_hid pcc_cpufreq acpi_cpufreq sg
ip_tables x_tables ext4(E) crc32c_generic(E) crc16(E) mbcache(E) jbd2(E)
fscrypto(E) sd_mod(E) hid_generic(E) usbhid(E) hid(E) dm_mod(E) serio_raw(E)
atkbd(E) libps2(E) crc32c_intel(E) ahci(E) libahci(E) libata(E) xhci
_pci(E) xhci_hcd(E)
Feb 28 19:27:45 kernel: scsi_mod(E) i8042(E) serio(E) bcache(E) crc64(E)
Feb 28 19:27:45 kernel: CPU: 2 PID: 896 Comm: cinnamon Tainted: GB W E
4.20.12-arch1-1-custom #1
Feb 28 19:27:45 kernel: Hardware name: To Be Filled By O.E.M. To Be Filled By
O.E.M./B450M Pro4, BIOS P1.20 06/26/2018
Feb 28 19:27:45 kernel: Call Trace:
Feb 28 19:27:45 kernel: dump_stack+0x5c/0x80
Feb 28 19:27:45 kernel: bad_page.cold.29+0x7f/0xb2
Feb 28 19:27:45 kernel: __free_pages_ok+0x2c0/0x2d0
Feb 28 19:27:45 kernel: skb_release_data+0x96/0x180
Feb 28 19:27:45 kernel: __kfree_skb+0xe/0x20
Feb 28 19:27:45 kernel: tcp_recvmsg+0x894/0xc60
Feb 28 19:27:45 kernel: ? reuse_swap_page+0x120/0x340
Feb 28 19:27:45 kernel: ? ptep_set_access_flags+0x23/0x30
Feb 28 19:27:45 kernel: inet_recvmsg+0x5b/0x100
Feb 28 19:27:45 kernel: __sys_recvfrom+0xc3/0x180
Feb 28 19:27:45 kernel: ? handle_mm_fault+0x10a/0x250
Feb 28 19:27:45 kernel: ? syscall_trace_enter+0x1d3/0x2d0
Feb 28 19:27:45 kernel: ? __audit_syscall_exit+0x22a/0x290
Feb 28 19:27:45 kernel: __x64_sys_recvfrom+0x24/0x30
Feb 28 19:27:45 kernel: do_syscall_64+0x5b/0x170
Feb 28 19:27:45 kernel: entry_SYSCALL_64_after_hwframe+0x44/0xa9
Cc: sta...@vger.kernel.org
Reported-and-tested-by: Jan Viktorin
Reviewed-by: Alexander Duyck
Signed-off-by: Stanislaw Gruszka
---
v2: add comment
drivers/iommu/amd_iommu.c | 6 +-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 6b0760dafb3e..696c78225dd1 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2604,7 +2604,11 @@ static int map_sg(struct device *dev, struct scatterlist
*sglist,
/* Everything is mapped - write the right values into s->dma_address */
for_each_sg(sglist, s, nelems, i) {
- s->dma_address += address + s->offset;
+ /* Add in the remaining piece of the scatter-gather offset that
+* was masked out when we were determining the physical address
+* via (sg_phys(s) & PAGE_MASK) earlier.
+*/
+ s->dma_address += address + (s->offset & ~PAGE_MASK);
s->dma_length = s->length;
}
--
2.7.5
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