[PATCH 2/2] scsi: mpt3sas: Avoid IOMMU page faults on report zones

Damien Le Moal
2024-07-19T07:39:17Z

Some firmware versions of the 9600 series SAS HBA byte-swap the report
zone command reply buffer from ATA-ZAC devices by directly accessing
the buffer in the host memory. This does not respect the default
command DMA direction and causes IOMMU page faults on architectures
with an IOMMU enforcing write-only mappings for DMA_FROM_DEVICE DMA
driection (e.g. AMD hosts).

scsi 18:0:0:0: Direct-Access-ZBC ATA WDC WSH722020AL W870 PQ: 0 ANSI: 6
scsi 18:0:0:0: SATA: handle(0x0027), sas_addr(0x300062b2083e7c40), phy(0), device_name(0x5000cca29dc35e11)
scsi 18:0:0:0: enclosure logical id (0x300062b208097c40), slot(0)
scsi 18:0:0:0: enclosure level(0x0000), connector name( C0.0)
scsi 18:0:0:0: atapi(n), ncq(y), asyn_notify(n), smart(y), fua(y), sw_preserve(y)
scsi 18:0:0:0: qdepth(32), tagged(1), scsi_level(7), cmd_que(1)
sd 18:0:0:0: Attached scsi generic sg2 type 20
sd 18:0:0:0: [sdc] Host-managed zoned block device
mpt3sas 0000:41:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0021 address=0xfff9b200 flags=0x0050]
mpt3sas 0000:41:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0021 address=0xfff9b300 flags=0x0050]
mpt3sas_cm0: mpt3sas_ctl_pre_reset_handler: Releasing the trace buffer due to adapter reset.
mpt3sas_cm0 fault info from func: mpt3sas_base_make_ioc_ready
mpt3sas_cm0: fault_state(0x2666)!
mpt3sas_cm0: sending diag reset !!
mpt3sas_cm0: diag reset: SUCCESS
sd 18:0:0:0: [sdc] REPORT ZONES start lba 0 failed
sd 18:0:0:0: [sdc] REPORT ZONES: Result: hostbyte=DID_RESET driverbyte=DRIVER_OK
sd 18:0:0:0: [sdc] 0 4096-byte logical blocks: (0 B/0 B)

Avoid such issue by always mapping the buffer of report zones commands
using DMA_BIDIRECTIONAL (read+write IOMMU mapping). This is done by
introducing the helper function _base_scsi_dma_map() and using this
helper in _base_build_sg_scmd() and _base_build_sg_scmd_ieee() instead
of calling directly scsi_dma_map().

Fixes: 471ef9d4e498 ("mpt3sas: Build MPI SGL LIST on GEN2 HBAs and IEEE SGL LIST on GEN3 HBAs")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
drivers/scsi/mpt3sas/mpt3sas_base.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index b2bcf4a27ddc..6e103875d672 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -2671,6 +2671,22 @@ _base_build_zero_len_sge_ieee(struct MPT3SAS_ADAPTER *ioc, void *paddr)
_base_add_sg_single_ieee(paddr, sgl_flags, 0, 0, -1);
}

+static inline int _base_scsi_dma_map(struct scsi_cmnd *cmd)
+{
+ /*
+ * Some firmware versions byte-swap the report zone command reply from
+ * ATA-ZAC devices by directly accessing in the host buffer. This does
+ * not respect the default command DMA direction and causes IOMMU page
+ * faults on some architectures with an IOMMU enforcing write mappings
+ * (e.g. AMD hosts). Avoid such issue by making the report zones buffer
+ * mapping bi-directional.
+ */
+ if (cmd->cmnd[0] == ZBC_IN && cmd->cmnd[1] == ZI_REPORT_ZONES)
+ cmd->sc_data_direction = DMA_BIDIRECTIONAL;
+
+ return scsi_dma_map(cmd);
+}
+
/**
* _base_build_sg_scmd - main sg creation routine
* pcie_device is unused here!
@@ -2717,7 +2733,7 @@ _base_build_sg_scmd(struct MPT3SAS_ADAPTER *ioc,
sgl_flags = sgl_flags << MPI2_SGE_FLAGS_SHIFT;

sg_scmd = scsi_sglist(scmd);
- sges_left = scsi_dma_map(scmd);
+ sges_left = _base_scsi_dma_map(scmd);
if (sges_left < 0)
return -ENOMEM;

@@ -2861,7 +2877,7 @@ _base_build_sg_scmd_ieee(struct MPT3SAS_ADAPTER *ioc,
}

sg_scmd = scsi_sglist(scmd);
- sges_left = scsi_dma_map(scmd);
+ sges_left = _base_scsi_dma_map(scmd);
if (sges_left < 0)
return -ENOMEM;

--
2.45.2