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Message-Id: <1668147701-4583-7-git-send-email-mikelley@microsoft.com> Date: Thu, 10 Nov 2022 22:21:35 -0800 From: Michael Kelley <mikelley@...rosoft.com> To: hpa@...or.com, kys@...rosoft.com, haiyangz@...rosoft.com, wei.liu@...nel.org, decui@...rosoft.com, luto@...nel.org, peterz@...radead.org, davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com, lpieralisi@...nel.org, robh@...nel.org, kw@...ux.com, bhelgaas@...gle.com, arnd@...db.de, hch@...radead.org, m.szyprowski@...sung.com, robin.murphy@....com, thomas.lendacky@....com, brijesh.singh@....com, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com, Tianyu.Lan@...rosoft.com, kirill.shutemov@...ux.intel.com, sathyanarayanan.kuppuswamy@...ux.intel.com, ak@...ux.intel.com, isaku.yamahata@...el.com, dan.j.williams@...el.com, jane.chu@...cle.com, seanjc@...gle.com, tony.luck@...el.com, x86@...nel.org, linux-kernel@...r.kernel.org, linux-hyperv@...r.kernel.org, netdev@...r.kernel.org, linux-pci@...r.kernel.org, linux-arch@...r.kernel.org, iommu@...ts.linux.dev Cc: mikelley@...rosoft.com Subject: [PATCH v2 06/12] 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 <mikelley@...rosoft.com> Acked-by: Christoph Hellwig <hch@....de> --- arch/x86/kernel/cpu/mshyperv.c | 7 +------ include/linux/swiotlb.h | 2 -- kernel/dma/swiotlb.c | 45 +----------------------------------------- 3 files changed, 2 insertions(+), 52 deletions(-) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index b080795..c87e411 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -18,7 +18,6 @@ #include <linux/kexec.h> #include <linux/i8253.h> #include <linux/random.h> -#include <linux/swiotlb.h> #include <asm/processor.h> #include <asm/hypervisor.h> #include <asm/hyperv-tlfs.h> @@ -332,12 +331,8 @@ static void __init ms_hyperv_init_platform(void) pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n", ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b); - if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) { + if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) static_branch_enable(&isolation_type_snp); -#ifdef CONFIG_SWIOTLB - swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary; -#endif - } } if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) { diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 35bc4e2..13d7075 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -185,6 +185,4 @@ static inline bool is_swiotlb_for_alloc(struct device *dev) } #endif /* CONFIG_DMA_RESTRICTED_POOL */ -extern phys_addr_t swiotlb_unencrypted_base; - #endif /* __LINUX_SWIOTLB_H */ diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index a34c38b..d3d6be0 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -73,8 +73,6 @@ struct io_tlb_slot { 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; @@ -210,34 +208,6 @@ static inline unsigned long nr_slots(u64 val) } /* - * 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 * call SWIOTLB when the operations are possible. It needs to be called @@ -246,18 +216,12 @@ 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, @@ -288,13 +252,6 @@ 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; -- 1.8.3.1
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