kernel/linux.git/arch/s390, branch v6.18.44

s390/pci: Fix s390_pci_mmio_write syscall error return without MIO

2026-08-09T18:25:19+00:00

commit b7ab86bdc65eadcfc43a0e3faf682a3f750cfb96 upstream. On a machine without PCI memory-I/O (MIO) support or when running with pci=nomio the s390 specific PCI MMIO write syscall checks if the MMIO cookie is above ZPCI_IOMAP_ADDR_BASE as a sanity check before even trying to perform the MMIO. If this check fails the return value was left unchanged and thus 0 from prior operations falsely indicating success. This could potentially confuse user-space into falsely believing the MMIO, on a mapping not valid for MMIO was successful. Fix this by setting the return value to -EFAULT prior to the check following the same pattern as elsewhere in the same function. Cc: stable@vger.kernel.org Reviewed-by: Julian Ruess Reviewed-by: Farhan Ali Fixes: a67a88b0b8de ("s390/pci: remove races against pte updates") Signed-off-by: Niklas Schnelle Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

KVM: s390: pci: Validate AIBV and AISB before pinning guest pages

2026-08-09T18:25:12+00:00

commit 868d32ac72cba21c5c6d8a66a814b7c25a3a5c01 upstream. The AIBV holds one bit per MSI-X vector for a given function. The size of the bit vector is derived from the NOI and the AIBVO. If the size of the AIBV exceeds a single page boundary, then reject the request as we cannot safely pin the guest AIBV. Similarly reject the request if the AISB address is not 8-byte aligned as the architecture requires doubleword alignment for the summary bit address. Since the AISBO can address up to 64 bits, the size of the AISB can only be 8 bytes for the function. This also ensures the AISB doesn't exceed a single page boundary. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Cc: stable@vger.kernel.org Reviewed-by: Christian Borntraeger Reviewed-by: Matthew Rosato Signed-off-by: Farhan Ali Tested-by: Matthew Rosato Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: pci: Fix NULL dereference on AIBV allocation failure

2026-08-09T18:25:12+00:00

commit 8bf09b9b7d3232806df95f409581f8a9fd99a3fa upstream. The airq_iv_create() can return NULL on failure, but the return value was never checked. If it fails, zdev->aibv will be NULL and fail when dereferenced in kvm_zpci_set_airq(). Add a NULL check and free the previously allocated AISB bit and zdev->aisb on failure. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Cc: stable@vger.kernel.org Reviewed-by: Christian Borntraeger Reviewed-by: Matthew Rosato Signed-off-by: Farhan Ali Tested-by: Matthew Rosato Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: pci: Fix missing error codes and memory unaccounting

2026-08-09T18:25:12+00:00

commit f86842e4d6c482300f4567f492d512c9ccf5bc4f upstream. In kvm_s390_pci_aif_enable() two error paths failed to set an error code, causing the function to return 0 on failure. It also failed to rollback memory accounting on failure. Fix both by propagating an error code on failure and calling unaccount_mem() in the cleanup path. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Cc: stable@vger.kernel.org Reviewed-by: Christian Borntraeger Reviewed-by: Matthew Rosato Signed-off-by: Farhan Ali Tested-by: Matthew Rosato Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: pci: Fix memory accounting for pinned/unpinned pages

2026-08-09T18:25:11+00:00

commit 36f6999ecde3976731a8bfc0b8e667da6f593069 upstream. The account_mem() and unaccount_mem() functions call get_uid() which increments the reference count of struct user_struct on every invocation. But we don't decrement the count by calling free_uid(). It also accounted/unaccounted the pages against the current->mm. But its possible the unaccount_mem() can be called from a different process context than the one that originally pinned the pages. Let's fix this by storing the pinning process user_struct and mm_struct when accounting for pinned pages, and subsequently free these resources when the pages are unpinned. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Cc: stable@vger.kernel.org Reviewed-by: Christian Borntraeger Reviewed-by: Matthew Rosato Signed-off-by: Farhan Ali Tested-by: Matthew Rosato [borntraeger@linux.ibm.com: Fixed whitespace] Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: pci: Reject adapter interrupt forwarding if already enabled

2026-08-09T18:25:11+00:00

commit 8fa01be5a6149404adb82c0979a78f6347edd3ef upstream. The MPCIFC instruction doesn't allow registering adapter interrupts without first unregistering. So reject any request to enable interrupt forwarding if its already enabled for the zPCI device. This also fixes overwriting and thus leaking resources when the ioctl is called multiple times for the same device. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Cc: stable@vger.kernel.org Reviewed-by: Christian Borntraeger Reviewed-by: Matthew Rosato Signed-off-by: Farhan Ali Tested-by: Matthew Rosato Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

s390/ptff: Export ptff_function_mask[]

2026-08-03T09:22:04+00:00

commit 9de445d8296a7f2b011ebb5834fdc94dcda5c778 upstream. Export the ptff_function_mask to make ptff_query() usable in modules. Signed-off-by: Sven Schnelle Acked-by: Heiko Carstens Link: https://patch.msgid.link/20260714130342.1971700-2-svens@linux.ibm.com Signed-off-by: Jakub Kicinski Cc: Jiri Slaby Signed-off-by: Greg Kroah-Hartman

s390/checksum: Fix csum_partial() without vector facility

2026-08-03T09:21:34+00:00

[ Upstream commit 4bb06b60d982355e22647b3d12d6619419f8c1fa ] Currently csum_partial() calls csum_copy() with copy=false and dst=NULL. On machines without the vector facility, csum_copy() falls back to cksm(dst, ...), causing the checksum to be calculated from address zero instead of the source buffer. The VX implementation already checksums data loaded from src. Make the fallback do the same by passing src to cksm(). Fixes: dcd3e1de9d17 ("s390/checksum: provide csum_partial_copy_nocheck()") Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin

s390/mm: Fix type mismatch in get_align_mask().

2026-07-24T14:17:16+00:00

commit ec84aad4c3594307d103af563991b4415ac5c8ab upstream. Commit 86f48f922ba79 ("s390/mmap: disable mmap alignment when randomize_va_space = 0") introduced get_align_mask() with return type of 'int', while the target field 'info.align_mask' in struct vm_unmapped_area_info is 'unsigned long'. With currently used masks, this should not cause truncation issues, but fix it and return 'unsigned long' to avoid future problems. Fixes: 86f48f922ba79 ("s390/mmap: disable mmap alignment when randomize_va_space = 0") Cc: stable@vger.kernel.org # v6.9+ Signed-off-by: Gerald Schaefer Reviewed-by: Sven Schnelle Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/diag: Add missing array_index_nospec() call to memtop_get_page_count()

2026-07-24T14:17:16+00:00

commit b7577fe4c47a31ca7c99714c53244a44af03cdfe upstream. 'level' is user space controlled and used to read from an array. Add the missing array_index_nospec() call to prevent speculative execution. Cc: stable@vger.kernel.org Fixes: 0d30871739ab ("s390/diag: Add memory topology information via diag310") Signed-off-by: Heiko Carstens Reviewed-by: Mete Durlu Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman