From fcbd538c875f5f1086682829671935d7155e4029 Mon Sep 17 00:00:00 2001 From: "GuoRui.Yu" Date: Sat, 28 Jan 2023 16:32:54 +0800 Subject: [PATCH] cc-swiotlb: Allow set swiotlb watermark from cmdline Signed-off-by: GuoRui.Yu --- .../admin-guide/kernel-parameters.txt | 11 ++++++ kernel/dma/cc-swiotlb.c | 34 ++++++++++++++++++- 2 files changed, 44 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6cfa6e3996cf75..ad510e39299825 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6090,6 +6090,17 @@ wouldn't be automatically used by the kernel noforce -- Never use bounce buffers (for debugging) + cc_swiotlb= [X86] + Format: { [, , , ]| force ]} + Set the swiotlb TLB buffer initial size for Confidential Computing like + TDX and SEV-SNP. + -- Number of I/O TLB of 256 bytes + -- Number of I/O TLB of 4 KiB + -- Number of I/O TLB of 64 KiB + -- Number of I/O TLB of 256 KiB + force -- force using of cc bounce buffers even if they + wouldn't be automatically used by the kernel (for debugging) + switches= [HW,M68k] sysctl.*= [KNL] diff --git a/kernel/dma/cc-swiotlb.c b/kernel/dma/cc-swiotlb.c index e85d3ce2272ff5..ff1cc52189b958 100644 --- a/kernel/dma/cc-swiotlb.c +++ b/kernel/dma/cc-swiotlb.c @@ -52,6 +52,32 @@ enum SLOT_SIZE { const unsigned int SLOT_SIZES[NR_OF_SIZES] = {512, 2048, 4096, 16 * 1024, 512 * 1024}; unsigned int WATERMARK_SLOT_SIZE[NR_OF_SIZES] = {256, 16384, 8192, 1024, 32}; +static bool swiotlb_force_bounce = false; + +static int __init +setup_io_tlb_watermark(char *str) +{ + int i; + size_t size; + + for (i = 0; i < NR_OF_SIZES; i++) { + if (isdigit(*str)) { + size = simple_strtoul(str, &str, 0); + WATERMARK_SLOT_SIZE[i] = size; + + if (*str == ',') + ++str; + } + else + break; + } + + if (!strcmp(str, "force")) + swiotlb_force_bounce = true; + + return 0; +} +early_param("cc_swiotlb", setup_io_tlb_watermark); struct slot_terrace { struct list_head slots_by_size[NR_OF_SIZES]; @@ -330,6 +356,7 @@ static void cc_populate_pages(void) size_t i, j, k; const size_t max_bytes_per_alloc = (MAX_ORDER_NR_PAGES << PAGE_SHIFT); size_t remain_alloc_size, rounds, round_size, round_slot_nr; + size_t size = 0; for (i = 0; i < NR_OF_SIZES; i++) { if (atomic_read(&terrace.free_count_by_size[i]) > WATERMARK_SLOT_SIZE[i]) @@ -377,6 +404,11 @@ static void cc_populate_pages(void) spin_unlock_irqrestore(&terrace.lock_by_size[i], flags); } } + + for (i = 0; i < NR_OF_SIZES; i++) { + size += (size_t)atomic_read(&terrace.total_count_by_size[i]) * SLOT_SIZES[i]; + } + pr_info("bounce buffer size adjusted to %luMB", size >> 20); } static int kccd(void *p) @@ -437,7 +469,7 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) return; } - io_tlb_default_mem.force_bounce = cc_platform_has(CC_ATTR_MEM_ENCRYPT); + io_tlb_default_mem.force_bounce = cc_platform_has(CC_ATTR_MEM_ENCRYPT) || swiotlb_force_bounce; xa_init_flags(io_tlb_default_mem.mapping, 0);