[PATCH 09/11] swiotlb: add a SWIOTLB_ANY flag to lift the low memory restriction
From: Christoph Hellwig <hch@lst.de>
Date: 2022-02-27 14:35:48
Also in:
linux-arm-kernel, linux-hyperv, linux-iommu, linux-mips, linux-pci, linux-riscv, linux-s390, xen-devel
Subsystem:
dma mapping helpers, linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Marek Szyprowski, Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Power SVM wants to allocate a swiotlb buffer that is not restricted to low memory for the trusted hypervisor scheme. Consolidate the support for this into the swiotlb_init interface by adding a new flag. Signed-off-by: Christoph Hellwig <hch@lst.de> --- arch/powerpc/include/asm/svm.h | 4 ---- arch/powerpc/mm/mem.c | 5 +---- arch/powerpc/platforms/pseries/svm.c | 26 +------------------------- include/linux/swiotlb.h | 1 + kernel/dma/swiotlb.c | 9 +++++++-- 5 files changed, 10 insertions(+), 35 deletions(-)
diff --git a/arch/powerpc/include/asm/svm.h b/arch/powerpc/include/asm/svm.h
index 7546402d796af..85580b30aba48 100644
--- a/arch/powerpc/include/asm/svm.h
+++ b/arch/powerpc/include/asm/svm.h@@ -15,8 +15,6 @@ static inline bool is_secure_guest(void) return mfmsr() & MSR_S; } -void __init svm_swiotlb_init(void); - void dtl_cache_ctor(void *addr); #define get_dtl_cache_ctor() (is_secure_guest() ? dtl_cache_ctor : NULL)
@@ -27,8 +25,6 @@ static inline bool is_secure_guest(void) return false; } -static inline void svm_swiotlb_init(void) {} - #define get_dtl_cache_ctor() NULL #endif /* CONFIG_PPC_SVM */
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index d99b8b5b40ca6..a4d65418c30a9 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c@@ -249,10 +249,7 @@ void __init mem_init(void) * back to to-down. */ memblock_set_bottom_up(true); - if (is_secure_guest()) - svm_swiotlb_init(); - else - swiotlb_init(ppc_swiotlb_enable, ppc_swiotlb_flags); + swiotlb_init(ppc_swiotlb_enable, ppc_swiotlb_flags); #endif high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
index c5228f4969eb2..3b4045d508ec8 100644
--- a/arch/powerpc/platforms/pseries/svm.c
+++ b/arch/powerpc/platforms/pseries/svm.c@@ -28,7 +28,7 @@ static int __init init_svm(void) * need to use the SWIOTLB buffer for DMA even if dma_capable() says * otherwise. */ - swiotlb_force = SWIOTLB_FORCE; + ppc_swiotlb_flags |= SWIOTLB_ANY | SWIOTLB_FORCE; /* Share the SWIOTLB buffer with the host. */ swiotlb_update_mem_attributes();
@@ -37,30 +37,6 @@ static int __init init_svm(void) } machine_early_initcall(pseries, init_svm); -/* - * Initialize SWIOTLB. Essentially the same as swiotlb_init(), except that it - * can allocate the buffer anywhere in memory. Since the hypervisor doesn't have - * any addressing limitation, we don't need to allocate it in low addresses. - */ -void __init svm_swiotlb_init(void) -{ - unsigned char *vstart; - unsigned long bytes, io_tlb_nslabs; - - io_tlb_nslabs = (swiotlb_size_or_default() >> IO_TLB_SHIFT); - io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); - - bytes = io_tlb_nslabs << IO_TLB_SHIFT; - - vstart = memblock_alloc(PAGE_ALIGN(bytes), PAGE_SIZE); - if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, false)) - return; - - - memblock_free(vstart, PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT)); - panic("SVM: Cannot allocate SWIOTLB buffer"); -} - int set_memory_encrypted(unsigned long addr, int numpages) { if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index dcecf953f7997..ee655f2e4d28b 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h@@ -15,6 +15,7 @@ struct scatterlist; #define SWIOTLB_VERBOSE (1 << 0) /* verbose initialization */ #define SWIOTLB_FORCE (1 << 1) /* force bounce buffering */ +#define SWIOTLB_ANY (1 << 2) /* allow any memory for the buffer */ /* * Maximum allowable number of contiguous slabs to map,
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index ad604e5a0983d..ec200e40fc397 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c@@ -275,8 +275,13 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) if (swiotlb_force_disable) return; - /* Get IO TLB memory from the low pages */ - tlb = memblock_alloc_low(bytes, PAGE_SIZE); + /* + * By default allocate the bonuce buffer memory from low memory. + */ + if (flags & SWIOTLB_ANY) + tlb = memblock_alloc(bytes, PAGE_SIZE); + else + tlb = memblock_alloc_low(bytes, PAGE_SIZE); if (!tlb) goto fail; if (swiotlb_init_with_tbl(tlb, default_nslabs, flags))
--
2.30.2