On Fri, 02 Oct 2026, Ilpo Järvinen <[email protected]> wrote: > pci=resource_alignment argument can override the default alignment for > the resource. The remainder code introduced in the commit 9036bd0efcb6 > ("PCI: Align head space better") can move remainder space (non-aligning > part of the size) before the aligning left edge which results in > violating the requested alignment. > > Introduce struct pci_resreq_data to hold device and user-given alignment > to be able to honor it in pci_align_resource(). When user-given alignment > is found, any remainder movement is skipped. > > Fixes: 9036bd0efcb6 ("PCI: Align head space better") > Reported-by: Sashiko <[email protected]> > Link: > https://lore.kernel.org/linux-pci/[email protected]/ > Signed-off-by: Ilpo Järvinen <[email protected]>
So I don't have the time to figure out what's going on here, but assuming you get proper review, the i915 part is Acked-by: Jani Nikula <[email protected]> for merging via whichever tree makes sense. > --- > arch/alpha/kernel/pci.c | 3 ++- > arch/arm/kernel/bios32.c | 5 +++-- > arch/m68k/kernel/pcibios.c | 4 ++-- > arch/mips/pci/pci-generic.c | 5 +++-- > arch/mips/pci/pci-legacy.c | 5 +++-- > arch/parisc/kernel/pci.c | 5 +++-- > arch/powerpc/kernel/pci-common.c | 5 +++-- > arch/sh/drivers/pci/pci.c | 5 +++-- > arch/x86/pci/i386.c | 5 +++-- > arch/xtensa/kernel/pci.c | 5 +++-- > drivers/char/agp/intel-gtt.c | 5 ++++- > drivers/gpu/drm/i915/i915_gmch.c | 5 +++-- > drivers/pci/pci.c | 5 +++-- > drivers/pci/setup-res.c | 19 +++++++++++++------ > include/linux/pci.h | 26 ++++++++++++++++++++++++-- > 15 files changed, 75 insertions(+), 32 deletions(-) > > diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c > index 11df411b1d18..c5d725a9781f 100644 > --- a/arch/alpha/kernel/pci.c > +++ b/arch/alpha/kernel/pci.c > @@ -128,7 +128,8 @@ pcibios_align_resource(void *data, const struct resource > *res, > const struct resource *empty_res, > resource_size_t size, resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > struct pci_controller *hose = dev->sysdata; > unsigned long alignto; > resource_size_t start = res->start; > diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c > index ac0e890510da..3e61826f07fb 100644 > --- a/arch/arm/kernel/bios32.c > +++ b/arch/arm/kernel/bios32.c > @@ -564,7 +564,8 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > resource_size_t size, > resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > resource_size_t start = res->start; > struct pci_host_bridge *host_bridge; > > @@ -578,7 +579,7 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > start, size, align); > > if (res->flags & IORESOURCE_MEM) > - return pci_align_resource(dev, res, empty_res, size, align); > + return pci_align_resource(rr, res, empty_res, size, align); > > return start; > } > diff --git a/arch/m68k/kernel/pcibios.c b/arch/m68k/kernel/pcibios.c > index 7a9e60df79c5..3024408412bc 100644 > --- a/arch/m68k/kernel/pcibios.c > +++ b/arch/m68k/kernel/pcibios.c > @@ -31,14 +31,14 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > resource_size_t size, > resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > resource_size_t start = res->start; > > if ((res->flags & IORESOURCE_IO) && (start & 0x300)) > start = (start + 0x3ff) & ~0x3ff; > > if (res->flags & IORESOURCE_MEM) > - return pci_align_resource(dev, res, empty_res, size, align); > + return pci_align_resource(rr, res, empty_res, size, align); > > return start; > } > diff --git a/arch/mips/pci/pci-generic.c b/arch/mips/pci/pci-generic.c > index c2e23d0c1d77..7f3ecb91b85b 100644 > --- a/arch/mips/pci/pci-generic.c > +++ b/arch/mips/pci/pci-generic.c > @@ -25,7 +25,8 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > const struct resource *empty_res, > resource_size_t size, resource_size_t > align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > resource_size_t start = res->start; > struct pci_host_bridge *host_bridge; > > @@ -39,7 +40,7 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > start, size, align); > > if (res->flags & IORESOURCE_MEM) > - return pci_align_resource(dev, res, empty_res, size, align); > + return pci_align_resource(rr, res, empty_res, size, align); > > return start; > } > diff --git a/arch/mips/pci/pci-legacy.c b/arch/mips/pci/pci-legacy.c > index dae6dafdd6e0..82d4b01db64e 100644 > --- a/arch/mips/pci/pci-legacy.c > +++ b/arch/mips/pci/pci-legacy.c > @@ -55,7 +55,8 @@ pcibios_align_resource(void *data, const struct resource > *res, > const struct resource *empty_res, > resource_size_t size, resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > struct pci_controller *hose = dev->sysdata; > resource_size_t start = res->start; > > @@ -70,7 +71,7 @@ pcibios_align_resource(void *data, const struct resource > *res, > if (start & 0x300) > start = (start + 0x3ff) & ~0x3ff; > } else if (res->flags & IORESOURCE_MEM) { > - start = pci_align_resource(dev, res, empty_res, size, align); > + start = pci_align_resource(rr, res, empty_res, size, align); > > /* Make sure we start at our min on all hoses */ > if (start < PCIBIOS_MIN_MEM + hose->mem_resource->start) > diff --git a/arch/parisc/kernel/pci.c b/arch/parisc/kernel/pci.c > index 518f532ccddc..d582be996051 100644 > --- a/arch/parisc/kernel/pci.c > +++ b/arch/parisc/kernel/pci.c > @@ -193,7 +193,8 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > resource_size_t size, > resource_size_t alignment) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > resource_size_t align, start = res->start; > > pci_dbg(dev, "%pR: pcibios_align_resource(%lx, 0x%llx, 0x%llx), parent > %pR\n", > @@ -205,7 +206,7 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > if (align > alignment) > start = ALIGN(start, align); > else > - start = pci_align_resource(dev, res, empty_res, size, > alignment); > + start = pci_align_resource(rr, res, empty_res, size, alignment); > > return start; > } > diff --git a/arch/powerpc/kernel/pci-common.c > b/arch/powerpc/kernel/pci-common.c > index 4fc52c21fe5d..23594759cfe2 100644 > --- a/arch/powerpc/kernel/pci-common.c > +++ b/arch/powerpc/kernel/pci-common.c > @@ -1131,7 +1131,8 @@ resource_size_t pcibios_align_resource(void *data, > const struct resource *res, > resource_size_t size, > resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > resource_size_t start = res->start; > > if (res->flags & IORESOURCE_IO) { > @@ -1140,7 +1141,7 @@ resource_size_t pcibios_align_resource(void *data, > const struct resource *res, > if (start & 0x300) > start = (start + 0x3ff) & ~0x3ff; > } else if (res->flags & IORESOURCE_MEM) { > - start = pci_align_resource(dev, res, empty_res, size, align); > + start = pci_align_resource(rr, res, empty_res, size, align); > } > > return start; > diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c > index 878a27a1acfb..279f2770ff4b 100644 > --- a/arch/sh/drivers/pci/pci.c > +++ b/arch/sh/drivers/pci/pci.c > @@ -172,7 +172,8 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > resource_size_t size, > resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > struct pci_channel *hose = dev->sysdata; > resource_size_t start = res->start; > > @@ -186,7 +187,7 @@ resource_size_t pcibios_align_resource(void *data, const > struct resource *res, > if (start & 0x300) > start = (start + 0x3ff) & ~0x3ff; > } else if (res->flags & IORESOURCE_MEM) { > - start = pci_align_resource(dev, res, empty_res, size, align); > + start = pci_align_resource(rr, res, empty_res, size, align); > } > > return start; > diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c > index e2de26b82940..4178ae4380c2 100644 > --- a/arch/x86/pci/i386.c > +++ b/arch/x86/pci/i386.c > @@ -156,7 +156,8 @@ pcibios_align_resource(void *data, const struct resource > *res, > const struct resource *empty_res, > resource_size_t size, resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > resource_size_t start = res->start; > > if (res->flags & IORESOURCE_IO) { > @@ -165,7 +166,7 @@ pcibios_align_resource(void *data, const struct resource > *res, > if (start & 0x300) > start = (start + 0x3ff) & ~0x3ff; > } else if (res->flags & IORESOURCE_MEM) { > - start = pci_align_resource(dev, res, empty_res, size, align); > + start = pci_align_resource(rr, res, empty_res, size, align); > > /* The low 1MB range is reserved for ISA cards */ > if (start < BIOS_END) > diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c > index 305031551136..4e8ad4a3c9fe 100644 > --- a/arch/xtensa/kernel/pci.c > +++ b/arch/xtensa/kernel/pci.c > @@ -42,7 +42,8 @@ pcibios_align_resource(void *data, const struct resource > *res, > const struct resource *empty_res, > resource_size_t size, resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > + struct pci_dev *dev = rr->dev; > resource_size_t start = res->start; > > if (res->flags & IORESOURCE_IO) { > @@ -55,7 +56,7 @@ pcibios_align_resource(void *data, const struct resource > *res, > if (start & 0x300) > start = (start + 0x3ff) & ~0x3ff; > } else if (res->flags & IORESOURCE_MEM) { > - start = pci_align_resource(dev, res, empty_res, size, align); > + start = pci_align_resource(rr, res, empty_res, size, align); > } > > return start; > diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c > index bcc26785175d..2214347906a6 100644 > --- a/drivers/char/agp/intel-gtt.c > +++ b/drivers/char/agp/intel-gtt.c > @@ -1038,10 +1038,13 @@ static struct agp_memory > *intel_fake_agp_alloc_by_type(size_t pg_count, > > static int intel_alloc_chipset_flush_resource(void) > { > + struct pci_resreq_data rr; > int ret; > + > + pci_init_pci_resreq_data(&rr, intel_private.bridge_dev); > ret = pci_bus_alloc_resource(intel_private.bridge_dev->bus, > &intel_private.ifp_resource, PAGE_SIZE, > PAGE_SIZE, PCIBIOS_MIN_MEM, 0, > - pcibios_align_resource, > intel_private.bridge_dev); > + pcibios_align_resource, &rr); > > return ret; > } > diff --git a/drivers/gpu/drm/i915/i915_gmch.c > b/drivers/gpu/drm/i915/i915_gmch.c > index b0ef6ef577a3..d35097bebc0f 100644 > --- a/drivers/gpu/drm/i915/i915_gmch.c > +++ b/drivers/gpu/drm/i915/i915_gmch.c > @@ -38,6 +38,7 @@ static int mchbar_reg(struct drm_i915_private *i915) > static int > intel_alloc_mchbar_resource(struct drm_i915_private *i915) > { > + struct pci_resreq_data rr; > u32 temp_lo, temp_hi = 0; > u64 mchbar_addr; > int ret; > @@ -55,12 +56,12 @@ intel_alloc_mchbar_resource(struct drm_i915_private *i915) > /* Get some space for it */ > i915->gmch.mch_res.name = "i915 MCHBAR"; > i915->gmch.mch_res.flags = IORESOURCE_MEM; > + pci_init_pci_resreq_data(&rr, i915->gmch.pdev); > ret = pci_bus_alloc_resource(i915->gmch.pdev->bus, > &i915->gmch.mch_res, > MCHBAR_SIZE, MCHBAR_SIZE, > PCIBIOS_MIN_MEM, > - 0, pcibios_align_resource, > - i915->gmch.pdev); > + 0, pcibios_align_resource, &rr); > if (ret) { > drm_dbg(&i915->drm, "failed bus alloc: %d\n", ret); > i915->gmch.mch_res.start = 0; > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index b2879a6be5f8..1b7a4469c6ca 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -6444,8 +6444,8 @@ static DEFINE_SPINLOCK(resource_alignment_lock); > * RETURNS: Resource alignment if it is specified. > * Zero if it is not specified. > */ > -static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, > - bool *resize) > +resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, > + bool *resize) > { > int align_order, count; > resource_size_t align = pcibios_default_alignment(); > @@ -6497,6 +6497,7 @@ static resource_size_t > pci_specified_resource_alignment(struct pci_dev *dev, > spin_unlock(&resource_alignment_lock); > return align; > } > +EXPORT_SYMBOL_GPL(pci_specified_resource_alignment); > > static void pci_request_resource_alignment(struct pci_dev *dev, int bar, > resource_size_t align, bool resize) > diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c > index 376f09630a4a..441a62807719 100644 > --- a/drivers/pci/setup-res.c > +++ b/drivers/pci/setup-res.c > @@ -265,17 +265,21 @@ resource_size_t pci_resource_alignment(const struct > pci_dev *dev, > * before res->start if there's enough free space there. This enables > * tighter packing for resources. > */ > -resource_size_t pci_align_resource(struct pci_dev *dev, > +resource_size_t pci_align_resource(struct pci_resreq_data *rr, > const struct resource *res, > const struct resource *empty_res, > resource_size_t size, > resource_size_t align) > { > + struct pci_dev *dev = rr->dev; > resource_size_t remainder, start_addr; > > if (!(res->flags & IORESOURCE_MEM)) > return res->start; > > + if (rr->user_align) > + return res->start; > + > if (IS_ALIGNED(size, align)) > return res->start; > > @@ -306,18 +310,21 @@ resource_size_t __weak pcibios_align_resource(void > *data, > resource_size_t size, > resource_size_t align) > { > - struct pci_dev *dev = data; > + struct pci_resreq_data *rr = data; > > - return pci_align_resource(dev, res, empty_res, size, align); > + return pci_align_resource(rr, res, empty_res, size, align); > } > > static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev, > int resno, resource_size_t size, resource_size_t align) > { > struct resource *res = pci_resource_n(dev, resno); > + struct pci_resreq_data rr; > resource_size_t min; > int ret; > > + pci_init_pci_resreq_data(&rr, dev); > + > min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM; > > /* > @@ -329,7 +336,7 @@ static int __pci_assign_resource(struct pci_bus *bus, > struct pci_dev *dev, > */ > ret = pci_bus_alloc_resource(bus, res, size, align, min, > IORESOURCE_PREFETCH | IORESOURCE_MEM_64, > - pcibios_align_resource, dev); > + pcibios_align_resource, &rr); > if (ret == 0) > return 0; > > @@ -341,7 +348,7 @@ static int __pci_assign_resource(struct pci_bus *bus, > struct pci_dev *dev, > (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) { > ret = pci_bus_alloc_resource(bus, res, size, align, min, > IORESOURCE_PREFETCH, > - pcibios_align_resource, dev); > + pcibios_align_resource, &rr); > if (ret == 0) > return 0; > } > @@ -354,7 +361,7 @@ static int __pci_assign_resource(struct pci_bus *bus, > struct pci_dev *dev, > */ > if (res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) > ret = pci_bus_alloc_resource(bus, res, size, align, min, 0, > - pcibios_align_resource, dev); > + pcibios_align_resource, &rr); > > return ret; > } > diff --git a/include/linux/pci.h b/include/linux/pci.h > index d31a8d107b1e..fe0233f0d9e6 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1217,12 +1217,34 @@ int __must_check pcibios_enable_device(struct pci_dev > *, int mask); > /* Architecture-specific versions may override this (weak) */ > char *pcibios_setup(char *str); > > -/* Used only when drivers/pci/setup.c is used */ > +/* Resource assignment request handling */ > +/** > + * struct pci_resreq_data - Data passed to pcibios_align_resource() > + * @dev: PCI device > + * @user_align: User provided alignment override (pci=resource_alignment > param) > + */ > +struct pci_resreq_data { > + struct pci_dev *dev; > + resource_size_t user_align; > +}; > + > +resource_size_t pci_specified_resource_alignment(struct pci_dev *dev, > + bool *resize); > +static inline void pci_init_pci_resreq_data(struct pci_resreq_data *rr, > + struct pci_dev *dev) > +{ > + bool user_aligned; > + > + memset(rr, 0, sizeof(*rr)); > + rr->dev = dev; > + rr->user_align = pci_specified_resource_alignment(dev, &user_aligned); > +} > + > resource_size_t pcibios_align_resource(void *data, const struct resource > *res, > const struct resource *empty_res, > resource_size_t size, > resource_size_t align); > -resource_size_t pci_align_resource(struct pci_dev *dev, > +resource_size_t pci_align_resource(struct pci_resreq_data *rr, > const struct resource *res, > const struct resource *empty_res, > resource_size_t size, -- Jani Nikula, Intel
