Messages in this thread |  | | Subject | Re: [RFC v2 28/32] x86/tdx: Make pages shared in ioremap() | | From | "Kuppuswamy, Sathyanarayanan" <> | | Date | Wed, 26 May 2021 14:37:39 -0700 |
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On 5/21/21 9:19 AM, Tom Lendacky wrote: > In arch/x86/mm/mem_encrypt.c, sme_early_init() (should have renamed that > when SEV support was added), we do: > if (sev_active()) > swiotlb_force = SWIOTLB_FORCE; > > TDX should be able to do a similar thing without having to touch > arch/x86/kernel/pci-swiotlb.c. > > That would remove any confusion over SME being part of a > protected_guest_has() call.
You mean sme_active() check in arch/x86/kernel/pci-swiotlb.c is redundant?
41 int __init pci_swiotlb_detect_4gb(void) 42 { 43 /* don't initialize swiotlb if iommu=off (no_iommu=1) */ 44 if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN) 45 swiotlb = 1; 46 47 /* 48 * If SME is active then swiotlb will be set to 1 so that bounce 49 * buffers are allocated and used for devices that do not support 50 * the addressing range required for the encryption mask. 51 */ 52 if (sme_active() || is_tdx_guest()) 53 swiotlb = 1;
-- Sathyanarayanan Kuppuswamy Linux Kernel Developer
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