From 16d990a15491cf76cd6eef0846e1b4100e63261a Mon Sep 17 00:00:00 2001 From: Junrui Luo Date: Wed, 15 Apr 2026 17:26:55 +0800 Subject: [PATCH 1/2] KVM: s390: pci: fix GAIT table indexing due to double-scaling pointer arithmetic kvm_s390_pci_aif_enable(), kvm_s390_pci_aif_disable(), and aen_host_forward() index the GAIT by manually multiplying the index with sizeof(struct zpci_gaite). Since aift->gait is already a struct zpci_gaite pointer, this double-scales the offset, accessing element aisb*16 instead of aisb. This causes out-of-bounds accesses when aisb >= 32 (with ZPCI_NR_DEVICES=512) Fix by removing the erroneous sizeof multiplication. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Fixes: 73f91b004321 ("KVM: s390: pci: enable host forwarding of Adapter Event Notifications") Reported-by: Yuhao Jiang Cc: stable@vger.kernel.org Signed-off-by: Junrui Luo Reviewed-by: Christian Borntraeger Reviewed-by: Matthew Rosato Tested-by: Matthew Rosato Signed-off-by: Christian Borntraeger --- arch/s390/kvm/interrupt.c | 3 +-- arch/s390/kvm/pci.c | 6 ++---- 2 files changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 7cb8ce833b62..f48f25c7dc8f 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -3307,8 +3307,7 @@ static void aen_host_forward(unsigned long si) struct zpci_gaite *gaite; struct kvm *kvm; - gaite = (struct zpci_gaite *)aift->gait + - (si * sizeof(struct zpci_gaite)); + gaite = aift->gait + si; if (gaite->count == 0) return; if (gaite->aisb != 0) diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c index 86d93e8dddae..eed45af1a92d 100644 --- a/arch/s390/kvm/pci.c +++ b/arch/s390/kvm/pci.c @@ -290,8 +290,7 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, phys_to_virt(fib->fmt0.aibv)); spin_lock_irq(&aift->gait_lock); - gaite = (struct zpci_gaite *)aift->gait + (zdev->aisb * - sizeof(struct zpci_gaite)); + gaite = aift->gait + zdev->aisb; /* If assist not requested, host will get all alerts */ if (assist) @@ -357,8 +356,7 @@ static int kvm_s390_pci_aif_disable(struct zpci_dev *zdev, bool force) if (zdev->kzdev->fib.fmt0.aibv == 0) goto out; spin_lock_irq(&aift->gait_lock); - gaite = (struct zpci_gaite *)aift->gait + (zdev->aisb * - sizeof(struct zpci_gaite)); + gaite = aift->gait + zdev->aisb; isc = gaite->gisc; gaite->count--; if (gaite->count == 0) { From 0cfe660559e857d7c00ab86c73e4510ce069086f Mon Sep 17 00:00:00 2001 From: Matthew Rosato Date: Fri, 24 Apr 2026 15:39:00 -0400 Subject: [PATCH 2/2] KVM: s390: pci: Fix aisb calculation The current implementation of aisb calculation will erroneously index via an unsigned long * as well as multiply by 8B for every 64-bits in the offset; only one or the other is required. This throws off aisb calculations once the number of devices exceeds 64, and can result in out-of-bounds access as well as failure to indicate summary bits associated with those devices in guests. Fix this by converting to a physical address before applying the offset, as is already done in arch/s390/pci/pci_irq.c. Fixes: 3c5a1b6f0a18 ("KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding") Signed-off-by: Matthew Rosato Reviewed-by: Niklas Schnelle Signed-off-by: Christian Borntraeger --- arch/s390/kvm/pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c index eed45af1a92d..5b075c38998e 100644 --- a/arch/s390/kvm/pci.c +++ b/arch/s390/kvm/pci.c @@ -166,7 +166,7 @@ static int kvm_zpci_set_airq(struct zpci_dev *zdev) fib.fmt0.noi = airq_iv_end(zdev->aibv); fib.fmt0.aibv = virt_to_phys(zdev->aibv->vector); fib.fmt0.aibvo = 0; - fib.fmt0.aisb = virt_to_phys(aift->sbv->vector + (zdev->aisb / 64) * 8); + fib.fmt0.aisb = virt_to_phys(aift->sbv->vector) + (zdev->aisb / 64) * 8; fib.fmt0.aisbo = zdev->aisb & 63; fib.gd = zdev->gisa; @@ -308,7 +308,7 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, /* Update guest FIB for re-issue */ fib->fmt0.aisbo = zdev->aisb & 63; - fib->fmt0.aisb = virt_to_phys(aift->sbv->vector + (zdev->aisb / 64) * 8); + fib->fmt0.aisb = virt_to_phys(aift->sbv->vector) + (zdev->aisb / 64) * 8; fib->fmt0.isc = gisc; /* Save some guest fib values in the host for later use */