* [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping
@ 2026-02-12 19:23 Justin Tee
2026-02-12 19:32 ` Mathias Krause
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Justin Tee @ 2026-02-12 19:23 UTC (permalink / raw)
To: linux-scsi; +Cc: jsmart833426, justin.tee, Mathias Krause, Justin Tee
From: Mathias Krause <minipli@grsecurity.net>
Using set_memory_wc() to enable write-combining for the DPP portion of
the MMIO mapping is wrong as set_memory_*() is meant to operate on RAM
only, not MMIO mappings. In fact, as used currently triggers a BUG_ON()
with enabled CONFIG_DEBUG_VIRTUAL.
Simply map the DPP region separately and in addition to the already
existing mappings, avoiding any possible negative side effects for
these.
Fixes: 1351e69fc6db ("scsi: lpfc: Add push-to-adapter support to sli4")
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Justin Tee <justintee8345@gmail.com>
---
drivers/scsi/lpfc/lpfc_init.c | 2 ++
drivers/scsi/lpfc/lpfc_sli.c | 36 +++++++++++++++++++++++++++++------
drivers/scsi/lpfc/lpfc_sli4.h | 3 +++
3 files changed, 35 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index a116a16c4a6f..b5e53c7d33e7 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -12039,6 +12039,8 @@ lpfc_sli4_pci_mem_unset(struct lpfc_hba *phba)
iounmap(phba->sli4_hba.conf_regs_memmap_p);
if (phba->sli4_hba.dpp_regs_memmap_p)
iounmap(phba->sli4_hba.dpp_regs_memmap_p);
+ if (phba->sli4_hba.dpp_regs_memmap_wc_p)
+ iounmap(phba->sli4_hba.dpp_regs_memmap_wc_p);
break;
case LPFC_SLI_INTF_IF_TYPE_1:
break;
diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 734af3d039f8..690763e0aa55 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -15981,6 +15981,32 @@ lpfc_dual_chute_pci_bar_map(struct lpfc_hba *phba, uint16_t pci_barset)
return NULL;
}
+static __maybe_unused void __iomem *
+lpfc_dpp_wc_map(struct lpfc_hba *phba, uint8_t dpp_barset)
+{
+
+ /* DPP region is supposed to cover 64-bit BAR2 */
+ if (dpp_barset != WQ_PCI_BAR_4_AND_5) {
+ lpfc_log_msg(phba, KERN_WARNING, LOG_INIT,
+ "3273 dpp_barset x%x != WQ_PCI_BAR_4_AND_5\n",
+ dpp_barset);
+ return NULL;
+ }
+
+ if (!phba->sli4_hba.dpp_regs_memmap_wc_p) {
+ void __iomem *dpp_map;
+
+ dpp_map = ioremap_wc(phba->pci_bar2_map,
+ pci_resource_len(phba->pcidev,
+ PCI_64BIT_BAR4));
+
+ if (dpp_map)
+ phba->sli4_hba.dpp_regs_memmap_wc_p = dpp_map;
+ }
+
+ return phba->sli4_hba.dpp_regs_memmap_wc_p;
+}
+
/**
* lpfc_modify_hba_eq_delay - Modify Delay Multiplier on EQs
* @phba: HBA structure that EQs are on.
@@ -16944,9 +16970,6 @@ lpfc_wq_create(struct lpfc_hba *phba, struct lpfc_queue *wq,
uint8_t dpp_barset;
uint32_t dpp_offset;
uint8_t wq_create_version;
-#ifdef CONFIG_X86
- unsigned long pg_addr;
-#endif
/* sanity check on queue memory */
if (!wq || !cq)
@@ -17132,14 +17155,15 @@ lpfc_wq_create(struct lpfc_hba *phba, struct lpfc_queue *wq,
#ifdef CONFIG_X86
/* Enable combined writes for DPP aperture */
- pg_addr = (unsigned long)(wq->dpp_regaddr) & PAGE_MASK;
- rc = set_memory_wc(pg_addr, 1);
- if (rc) {
+ bar_memmap_p = lpfc_dpp_wc_map(phba, dpp_barset);
+ if (!bar_memmap_p) {
lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
"3272 Cannot setup Combined "
"Write on WQ[%d] - disable DPP\n",
wq->queue_id);
phba->cfg_enable_dpp = 0;
+ } else {
+ wq->dpp_regaddr = bar_memmap_p + dpp_offset;
}
#else
phba->cfg_enable_dpp = 0;
diff --git a/drivers/scsi/lpfc/lpfc_sli4.h b/drivers/scsi/lpfc/lpfc_sli4.h
index ee58383492b2..b6d90604bb61 100644
--- a/drivers/scsi/lpfc/lpfc_sli4.h
+++ b/drivers/scsi/lpfc/lpfc_sli4.h
@@ -785,6 +785,9 @@ struct lpfc_sli4_hba {
void __iomem *dpp_regs_memmap_p; /* Kernel memory mapped address for
* dpp registers
*/
+ void __iomem *dpp_regs_memmap_wc_p;/* Kernel memory mapped address for
+ * dpp registers with write combining
+ */
union {
struct {
/* IF Type 0, BAR 0 PCI cfg space reg mem map */
--
2.38.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping
2026-02-12 19:23 [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping Justin Tee
@ 2026-02-12 19:32 ` Mathias Krause
2026-02-18 2:11 ` Martin K. Petersen
2026-02-24 16:47 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Mathias Krause @ 2026-02-12 19:32 UTC (permalink / raw)
To: Justin Tee, linux-scsi; +Cc: jsmart833426, justin.tee
On 12.02.26 20:23, Justin Tee wrote:
> From: Mathias Krause <minipli@grsecurity.net>
>
> Using set_memory_wc() to enable write-combining for the DPP portion of
> the MMIO mapping is wrong as set_memory_*() is meant to operate on RAM
> only, not MMIO mappings. In fact, as used currently triggers a BUG_ON()
> with enabled CONFIG_DEBUG_VIRTUAL.
>
> Simply map the DPP region separately and in addition to the already
> existing mappings, avoiding any possible negative side effects for
> these.
>
> Fixes: 1351e69fc6db ("scsi: lpfc: Add push-to-adapter support to sli4")
> Signed-off-by: Mathias Krause <minipli@grsecurity.net>
> Signed-off-by: Justin Tee <justintee8345@gmail.com>
> ---
> drivers/scsi/lpfc/lpfc_init.c | 2 ++
> drivers/scsi/lpfc/lpfc_sli.c | 36 +++++++++++++++++++++++++++++------
> drivers/scsi/lpfc/lpfc_sli4.h | 3 +++
> 3 files changed, 35 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
> index a116a16c4a6f..b5e53c7d33e7 100644
> --- a/drivers/scsi/lpfc/lpfc_init.c
> +++ b/drivers/scsi/lpfc/lpfc_init.c
> @@ -12039,6 +12039,8 @@ lpfc_sli4_pci_mem_unset(struct lpfc_hba *phba)
> iounmap(phba->sli4_hba.conf_regs_memmap_p);
> if (phba->sli4_hba.dpp_regs_memmap_p)
> iounmap(phba->sli4_hba.dpp_regs_memmap_p);
> + if (phba->sli4_hba.dpp_regs_memmap_wc_p)
> + iounmap(phba->sli4_hba.dpp_regs_memmap_wc_p);
> break;
> case LPFC_SLI_INTF_IF_TYPE_1:
> break;
> diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
> index 734af3d039f8..690763e0aa55 100644
> --- a/drivers/scsi/lpfc/lpfc_sli.c
> +++ b/drivers/scsi/lpfc/lpfc_sli.c
> @@ -15981,6 +15981,32 @@ lpfc_dual_chute_pci_bar_map(struct lpfc_hba *phba, uint16_t pci_barset)
> return NULL;
> }
>
> +static __maybe_unused void __iomem *
> +lpfc_dpp_wc_map(struct lpfc_hba *phba, uint8_t dpp_barset)
> +{
> +
> + /* DPP region is supposed to cover 64-bit BAR2 */
> + if (dpp_barset != WQ_PCI_BAR_4_AND_5) {
> + lpfc_log_msg(phba, KERN_WARNING, LOG_INIT,
> + "3273 dpp_barset x%x != WQ_PCI_BAR_4_AND_5\n",
> + dpp_barset);
> + return NULL;
> + }
> +
> + if (!phba->sli4_hba.dpp_regs_memmap_wc_p) {
> + void __iomem *dpp_map;
> +
> + dpp_map = ioremap_wc(phba->pci_bar2_map,
> + pci_resource_len(phba->pcidev,
> + PCI_64BIT_BAR4));
> +
> + if (dpp_map)
> + phba->sli4_hba.dpp_regs_memmap_wc_p = dpp_map;
> + }
> +
> + return phba->sli4_hba.dpp_regs_memmap_wc_p;
> +}
> +
> /**
> * lpfc_modify_hba_eq_delay - Modify Delay Multiplier on EQs
> * @phba: HBA structure that EQs are on.
> @@ -16944,9 +16970,6 @@ lpfc_wq_create(struct lpfc_hba *phba, struct lpfc_queue *wq,
> uint8_t dpp_barset;
> uint32_t dpp_offset;
> uint8_t wq_create_version;
> -#ifdef CONFIG_X86
> - unsigned long pg_addr;
> -#endif
>
> /* sanity check on queue memory */
> if (!wq || !cq)
> @@ -17132,14 +17155,15 @@ lpfc_wq_create(struct lpfc_hba *phba, struct lpfc_queue *wq,
>
> #ifdef CONFIG_X86
> /* Enable combined writes for DPP aperture */
> - pg_addr = (unsigned long)(wq->dpp_regaddr) & PAGE_MASK;
> - rc = set_memory_wc(pg_addr, 1);
> - if (rc) {
> + bar_memmap_p = lpfc_dpp_wc_map(phba, dpp_barset);
> + if (!bar_memmap_p) {
> lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
> "3272 Cannot setup Combined "
> "Write on WQ[%d] - disable DPP\n",
> wq->queue_id);
> phba->cfg_enable_dpp = 0;
> + } else {
> + wq->dpp_regaddr = bar_memmap_p + dpp_offset;
> }
> #else
> phba->cfg_enable_dpp = 0;
> diff --git a/drivers/scsi/lpfc/lpfc_sli4.h b/drivers/scsi/lpfc/lpfc_sli4.h
> index ee58383492b2..b6d90604bb61 100644
> --- a/drivers/scsi/lpfc/lpfc_sli4.h
> +++ b/drivers/scsi/lpfc/lpfc_sli4.h
> @@ -785,6 +785,9 @@ struct lpfc_sli4_hba {
> void __iomem *dpp_regs_memmap_p; /* Kernel memory mapped address for
> * dpp registers
> */
> + void __iomem *dpp_regs_memmap_wc_p;/* Kernel memory mapped address for
> + * dpp registers with write combining
> + */
> union {
> struct {
> /* IF Type 0, BAR 0 PCI cfg space reg mem map */
Looks good to me, therefore:
Reviewed-by: Mathias Krause <minipli@grsecurity.net>
Thanks,
Mathias
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping
2026-02-12 19:23 [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping Justin Tee
2026-02-12 19:32 ` Mathias Krause
@ 2026-02-18 2:11 ` Martin K. Petersen
2026-02-24 16:47 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Martin K. Petersen @ 2026-02-18 2:11 UTC (permalink / raw)
To: Justin Tee; +Cc: linux-scsi, jsmart833426, justin.tee, Mathias Krause
Justin,
> Using set_memory_wc() to enable write-combining for the DPP portion of
> the MMIO mapping is wrong as set_memory_*() is meant to operate on RAM
> only, not MMIO mappings. In fact, as used currently triggers a
> BUG_ON() with enabled CONFIG_DEBUG_VIRTUAL.
Applied to 7.0/scsi-staging, thanks!
--
Martin K. Petersen
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping
2026-02-12 19:23 [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping Justin Tee
2026-02-12 19:32 ` Mathias Krause
2026-02-18 2:11 ` Martin K. Petersen
@ 2026-02-24 16:47 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Martin K. Petersen @ 2026-02-24 16:47 UTC (permalink / raw)
To: linux-scsi, Justin Tee
Cc: Martin K . Petersen, jsmart833426, justin.tee, Mathias Krause
On Thu, 12 Feb 2026 11:23:27 -0800, Justin Tee wrote:
> Using set_memory_wc() to enable write-combining for the DPP portion of
> the MMIO mapping is wrong as set_memory_*() is meant to operate on RAM
> only, not MMIO mappings. In fact, as used currently triggers a BUG_ON()
> with enabled CONFIG_DEBUG_VIRTUAL.
>
> Simply map the DPP region separately and in addition to the already
> existing mappings, avoiding any possible negative side effects for
> these.
>
> [...]
Applied to 7.0/scsi-fixes, thanks!
[1/1] scsi: lpfc: Properly set WC for DPP mapping
https://git.kernel.org/mkp/scsi/c/bffda93a51b4
--
Martin K. Petersen
^ permalink raw reply [flat|nested] 4+ messages in thread
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2026-02-12 19:23 [PATCH v2 1/1] scsi: lpfc: Properly set WC for DPP mapping Justin Tee
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