From 0459ff4873739986dccafbb417cfc69e71bdacf4 Mon Sep 17 00:00:00 2001 From: Michael Kelley Date: Sun, 26 Mar 2023 06:52:02 -0700 Subject: swiotlb: Remove bounce buffer remapping for Hyper-V With changes to how Hyper-V guest VMs flip memory between private (encrypted) and shared (decrypted), creating a second kernel virtual mapping for shared memory is no longer necessary. Everything needed for the transition to shared is handled by set_memory_decrypted(). As such, remove swiotlb_unencrypted_base and the associated code. Signed-off-by: Michael Kelley Acked-by: Christoph Hellwig Acked-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/1679838727-87310-8-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu --- kernel/dma/swiotlb.c | 45 +-------------------------------------------- 1 file changed, 1 insertion(+), 44 deletions(-) (limited to 'kernel/dma') diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index dac42a2ad588..0fb16bdbbcae 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -73,8 +73,6 @@ static bool swiotlb_force_disable; struct io_tlb_mem io_tlb_default_mem; -phys_addr_t swiotlb_unencrypted_base; - static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT; static unsigned long default_nareas; @@ -201,34 +199,6 @@ static inline unsigned long nr_slots(u64 val) return DIV_ROUND_UP(val, IO_TLB_SIZE); } -/* - * Remap swioltb memory in the unencrypted physical address space - * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP - * Isolation VMs). - */ -#ifdef CONFIG_HAS_IOMEM -static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes) -{ - void *vaddr = NULL; - - if (swiotlb_unencrypted_base) { - phys_addr_t paddr = mem->start + swiotlb_unencrypted_base; - - vaddr = memremap(paddr, bytes, MEMREMAP_WB); - if (!vaddr) - pr_err("Failed to map the unencrypted memory %pa size %lx.\n", - &paddr, bytes); - } - - return vaddr; -} -#else -static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes) -{ - return NULL; -} -#endif - /* * Early SWIOTLB allocation may be too early to allow an architecture to * perform the desired operations. This function allows the architecture to @@ -238,18 +208,12 @@ static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes) void __init swiotlb_update_mem_attributes(void) { struct io_tlb_mem *mem = &io_tlb_default_mem; - void *vaddr; unsigned long bytes; if (!mem->nslabs || mem->late_alloc) return; - vaddr = phys_to_virt(mem->start); bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT); - set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT); - - mem->vaddr = swiotlb_mem_remap(mem, bytes); - if (!mem->vaddr) - mem->vaddr = vaddr; + set_memory_decrypted((unsigned long)mem->vaddr, bytes >> PAGE_SHIFT); } static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start, @@ -280,13 +244,6 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start, mem->slots[i].alloc_size = 0; } - /* - * If swiotlb_unencrypted_base is set, the bounce buffer memory will - * be remapped and cleared in swiotlb_update_mem_attributes. - */ - if (swiotlb_unencrypted_base) - return; - memset(vaddr, 0, bytes); mem->vaddr = vaddr; return; -- cgit v1.2.3