From: Koichiro Den Date: Wed, 13 May 2026 02:49:14 +0000 (+0900) Subject: PCI: endpoint: pci-epf-vntb: Report 0-based doorbell vector via ntb_db_event() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=91fb4488cd615a39360bc4160a10cb3236189ba1;p=thirdparty%2Flinux.git PCI: endpoint: pci-epf-vntb: Report 0-based doorbell vector via ntb_db_event() ntb_db_event() expects the vector number to be relative to the first doorbell vector starting at 0. pci-epf-vntb reserves vector 0 for link events and uses higher vector indices for doorbells. By passing the raw slot index to ntb_db_event(), it effectively assumes that doorbell 0 maps to vector 1. However, because the host uses a legacy slot layout and writes doorbell 0 into the third slot, doorbell 0 ultimately appears as vector 2 from the NTB core perspective. Adjust pci-epf-vntb to: - skip the unused second slot, and - report doorbells as 0-based vectors (DB#0 -> vector 0). This change does not introduce a behavioral difference until .db_vector_count()/.db_vector_mask() are implemented, because without those callbacks NTB clients effectively ignore the vector number. Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP") Signed-off-by: Koichiro Den Signed-off-by: Manivannan Sadhasivam Signed-off-by: Bjorn Helgaas Reviewed-by: Frank Li Link: https://patch.msgid.link/20260513024923.451765-4-den@valinux.co.jp --- diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c index cc0b356973f3..d31e2eee0869 100644 --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c @@ -83,6 +83,12 @@ enum epf_ntb_bar { VNTB_BAR_NUM, }; +enum epf_irq_slot { + EPF_IRQ_LINK = 0, + EPF_IRQ_RESERVED_DB, /* Historically skipped slot */ + EPF_IRQ_DB_START, +}; + /* * +--------------------------------------------------+ Base * | | @@ -272,10 +278,11 @@ static void epf_ntb_cmd_handler(struct work_struct *work) ntb = container_of(work, struct epf_ntb, cmd_handler.work); - for (i = 1; i < ntb->db_count && !ntb->msi_doorbell; i++) { + for (i = EPF_IRQ_DB_START; i < ntb->db_count && !ntb->msi_doorbell; + i++) { if (ntb->epf_db[i]) { - atomic64_or(1 << (i - 1), &ntb->db); - ntb_db_event(&ntb->ntb, i); + atomic64_or(1 << (i - EPF_IRQ_DB_START), &ntb->db); + ntb_db_event(&ntb->ntb, i - EPF_IRQ_DB_START); ntb->epf_db[i] = 0; } } @@ -341,10 +348,10 @@ static irqreturn_t epf_ntb_doorbell_handler(int irq, void *data) struct epf_ntb *ntb = data; int i; - for (i = 1; i < ntb->db_count; i++) + for (i = EPF_IRQ_DB_START; i < ntb->db_count; i++) if (irq == ntb->epf->db_msg[i].virq) { - atomic64_or(1 << (i - 1), &ntb->db); - ntb_db_event(&ntb->ntb, i); + atomic64_or(1 << (i - EPF_IRQ_DB_START), &ntb->db); + ntb_db_event(&ntb->ntb, i - EPF_IRQ_DB_START); } return IRQ_HANDLED; @@ -1450,8 +1457,8 @@ static void vntb_epf_peer_db_work(struct work_struct *work) while (db_bits) { /* * pci_epc_raise_irq() for MSI expects a 1-based - * interrupt number. db_bit is zero-based, so add 3 to - * preserve the historical slot offset. + * interrupt number. The first usable doorbell starts + * at EPF_IRQ_DB_START in the legacy slot layout. * * Legacy mapping (kept for compatibility): * @@ -1465,7 +1472,7 @@ static void vntb_epf_peer_db_work(struct work_struct *work) * interoperability with older peers. */ db_bit = __ffs64(db_bits); - interrupt_num = db_bit + 3; + interrupt_num = db_bit + EPF_IRQ_DB_START + 1; db_bits &= ~BIT_ULL(db_bit); ret = pci_epc_raise_irq(epf->epc, func_no, vfunc_no,