6.9-stable review patch. If anyone has any objections, please let me know.
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From: Eric Farman farman@linux.ibm.com
[ Upstream commit 2ae157ec497d93c639a60e730e21ec9c66fa9a6e ]
The processing of a Transfer-In-Channel (TIC) CCW requires locating the target of the CCW in the channel program, and updating the address to reflect what will actually be sent to hardware.
An error exists where the 64-bit virtual address is truncated to 32-bits (variable "cda") when performing this math. Since s390 addresses of that size are 31-bits, this leaves that additional bit enabled such that the resulting I/O triggers a channel program check. This shows up occasionally when booting a KVM guest from a passthrough DASD device:
..snip... Interrupt Response Block Data: : 0x0000000000003990 Function Ctrl : [Start] Activity Ctrl : Status Ctrl : [Alert] [Primary] [Secondary] [Status-Pending] Device Status : Channel Status : [Program-Check] cpa=: 0x00000000008d0018 prev_ccw=: 0x0000000000000000 this_ccw=: 0x0000000000000000 ...snip... dasd-ipl: Failed to run IPL1 channel program
The channel program address of "0x008d0018" in the IRB doesn't look wrong, but tracing the CCWs shows the offending bit enabled:
ccw=0x0000012e808d0000 cda=00a0b030 ccw=0x0000012e808d0008 cda=00a0b038 ccw=0x0000012e808d0010 cda=808d0008 ccw=0x0000012e808d0018 cda=00a0b040
Fix the calculation of the TIC CCW's data address such that it points to a valid 31-bit address regardless of the input address.
Fixes: bd36cfbbb9e1 ("s390/vfio_ccw_cp: use new address translation helpers") Signed-off-by: Eric Farman farman@linux.ibm.com Reviewed-by: Heiko Carstens hca@linux.ibm.com Link: https://lore.kernel.org/r/20240628163738.3643513-1-farman@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/s390/cio/vfio_ccw_cp.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index 6e5c508b1e07c..5f6e102256276 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -490,13 +490,14 @@ static int ccwchain_fetch_tic(struct ccw1 *ccw, struct channel_program *cp) { struct ccwchain *iter; - u32 cda, ccw_head; + u32 offset, ccw_head;
list_for_each_entry(iter, &cp->ccwchain_list, next) { ccw_head = iter->ch_iova; if (is_cpa_within_range(ccw->cda, ccw_head, iter->ch_len)) { - cda = (u64)iter->ch_ccw + dma32_to_u32(ccw->cda) - ccw_head; - ccw->cda = u32_to_dma32(cda); + /* Calculate offset of TIC target */ + offset = dma32_to_u32(ccw->cda) - ccw_head; + ccw->cda = virt_to_dma32((void *)iter->ch_ccw + offset); return 0; } } @@ -914,7 +915,7 @@ void cp_update_scsw(struct channel_program *cp, union scsw *scsw) * in the ioctl directly. Path status changes etc. */ list_for_each_entry(chain, &cp->ccwchain_list, next) { - ccw_head = (u32)(u64)chain->ch_ccw; + ccw_head = dma32_to_u32(virt_to_dma32(chain->ch_ccw)); /* * On successful execution, cpa points just beyond the end * of the chain.