From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dongli Zhang Date: Mon, 04 Apr 2022 07:09:08 +0000 Subject: Re: [PATCH 12/15] swiotlb: provide swiotlb_init variants that remap the buffer Message-Id: <54ec407f-eda2-6e28-90f9-eb48b2ec8763@oracle.com> List-Id: References: <20220404050559.132378-1-hch@lst.de> <20220404050559.132378-13-hch@lst.de> In-Reply-To: <20220404050559.132378-13-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig , iommu@lists.linux-foundation.org Cc: Juergen Gross , Tom Lendacky , linux-s390@vger.kernel.org, Stefano Stabellini , linux-ia64@vger.kernel.org, Anshuman Khandual , Konrad Rzeszutek Wilk , Robin Murphy , x86@kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, tboot-devel@lists.sourceforge.net, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, xen-devel@lists.xenproject.org, Boris Ostrovsky , David Woodhouse , linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org On 4/3/22 10:05 PM, Christoph Hellwig wrote: > To shared more code between swiotlb and xen-swiotlb, offer a > swiotlb_init_remap interface and add a remap callback to > swiotlb_init_late that will allow Xen to remap the buffer the > buffer without duplicating much of the logic. > > Signed-off-by: Christoph Hellwig > --- > arch/x86/pci/sta2x11-fixup.c | 2 +- > include/linux/swiotlb.h | 5 ++++- > kernel/dma/swiotlb.c | 36 +++++++++++++++++++++++++++++++++--- > 3 files changed, 38 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c > index c7e6faf59a861..7368afc039987 100644 > --- a/arch/x86/pci/sta2x11-fixup.c > +++ b/arch/x86/pci/sta2x11-fixup.c > @@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev) > int size = STA2X11_SWIOTLB_SIZE; > /* First instance: register your own swiotlb area */ > dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size); > - if (swiotlb_init_late(size, GFP_DMA)) > + if (swiotlb_init_late(size, GFP_DMA, NULL)) > dev_emerg(&pdev->dev, "init swiotlb failed\n"); > } > list_add(&instance->list, &sta2x11_instance_list); > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > index ee655f2e4d28b..7b50c82f84ce9 100644 > --- a/include/linux/swiotlb.h > +++ b/include/linux/swiotlb.h > @@ -36,8 +36,11 @@ struct scatterlist; > > int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, unsigned int flags); > unsigned long swiotlb_size_or_default(void); > +void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, > + int (*remap)(void *tlb, unsigned long nslabs)); > +int swiotlb_init_late(size_t size, gfp_t gfp_mask, > + int (*remap)(void *tlb, unsigned long nslabs)); > extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs); > -int swiotlb_init_late(size_t size, gfp_t gfp_mask); > extern void __init swiotlb_update_mem_attributes(void); > > phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys, > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 119187afc65ec..d5fe8f5e08300 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -256,9 +256,11 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, > * Statically reserve bounce buffer space and initialize bounce buffer data > * structures for the software IO TLB used to implement the DMA API. > */ > -void __init swiotlb_init(bool addressing_limit, unsigned int flags) > +void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, > + int (*remap)(void *tlb, unsigned long nslabs)) > { > - size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT); > + unsigned long nslabs = default_nslabs; > + size_t bytes; > void *tlb; > > if (!addressing_limit && !swiotlb_force_bounce) > @@ -271,12 +273,23 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) > * allow to pick a location everywhere for hypervisors with guest > * memory encryption. > */ > +retry: > + bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT); > if (flags & SWIOTLB_ANY) > tlb = memblock_alloc(bytes, PAGE_SIZE); > else > tlb = memblock_alloc_low(bytes, PAGE_SIZE); > if (!tlb) > goto fail; > + if (remap && remap(tlb, nslabs) < 0) { > + memblock_free(tlb, PAGE_ALIGN(bytes)); > + > + nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE); > + if (nslabs < IO_TLB_MIN_SLABS) > + panic("%s: Failed to remap %zu bytes\n", > + __func__, bytes); > + goto retry; > + } > if (swiotlb_init_with_tbl(tlb, default_nslabs, flags)) > goto fail_free_mem; > return; > @@ -287,12 +300,18 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) > pr_warn("Cannot allocate buffer"); > } > > +void __init swiotlb_init(bool addressing_limit, unsigned int flags) > +{ > + return swiotlb_init_remap(addressing_limit, flags, NULL); > +} > + > /* > * Systems with larger DMA zones (those that don't support ISA) can > * initialize the swiotlb later using the slab allocator if needed. > * This should be just like above, but with some error catching. > */ > -int swiotlb_init_late(size_t size, gfp_t gfp_mask) > +int swiotlb_init_late(size_t size, gfp_t gfp_mask, > + int (*remap)(void *tlb, unsigned long nslabs)) > { > unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE); > unsigned long bytes; > @@ -303,6 +322,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask) > if (swiotlb_force_disable) > return 0; > > +retry: > order = get_order(nslabs << IO_TLB_SHIFT); > nslabs = SLABS_PER_PAGE << order; > bytes = nslabs << IO_TLB_SHIFT; > @@ -323,6 +343,16 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask) > (PAGE_SIZE << order) >> 20); > nslabs = SLABS_PER_PAGE << order; > } > + if (remap) > + rc = remap(vstart, nslabs); > + if (rc) { > + free_pages((unsigned long)vstart, order); > + "warning: 1 line adds whitespace errors." above when I was applying the patch for test. Dongli Zhang > + nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE); > + if (nslabs < IO_TLB_MIN_SLABS) > + return rc; > + goto retry; > + } > rc = swiotlb_late_init_with_tbl(vstart, nslabs); > if (rc) > free_pages((unsigned long)vstart, order); >