Re: [PATCH v3 10/14] arm64: Force device mappings to be non-secure shared
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2024-06-17 15:43:36
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kvm, kvmarm, linux-coco, lkml
On Mon, Jun 17, 2024 at 03:55:22PM +0100, Suzuki K Poulose wrote:
quoted hunk ↗ jump to hunk
On 17/06/2024 04:33, Michael Kelley wrote:quoted
From: Steven Price <steven.price@arm.com> Sent: Wednesday, June 5, 2024 2:30 AMquoted
From: Suzuki K Poulose <suzuki.poulose@arm.com> Device mappings (currently) need to be emulated by the VMM so must be mapped shared with the host. Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> --- arch/arm64/include/asm/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 11d614d83317..c986fde262c0 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h@@ -644,7 +644,7 @@ static inline void set_pud_at(struct mm_struct *mm, unsigned long addr, #define pgprot_writecombine(prot) \ __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN) #define pgprot_device(prot) \ - __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN) + __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN | PROT_NS_SHARED) #define pgprot_tagged(prot) \ __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_TAGGED)) #define pgprot_mhp pgprot_taggedIn v2 of the patches, Catalin raised a question about the need for pgprot_decrypted(). What was concluded? It still looks to me like pgprot_decrypted() and prot_encrypted() are needed, by dma_direct_mmap() and remap_oldmem_pfn_range(), respectively. Also, assuming Hyper-V supports CCA at some point, the Linux guest drivers for Hyper-V need pgprot_decrypted() in hv_ringbuffer_init().Right, I think we could simply do :diff --git a/arch/arm64/include/asm/pgtable.hb/arch/arm64/include/asm/pgtable.h index c986fde262c0..1ed45893d1e6 100644--- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h@@ -648,6 +648,10 @@ static inline void set_pud_at(struct mm_struct *mm,unsigned long addr, #define pgprot_tagged(prot) \ __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_TAGGED)) #define pgprot_mhp pgprot_tagged + +#define pgprot_decrypted(prot) __pgprot_modify(prot, PROT_NS_SHARED, PROT_NS_SHARED) +#define pgprot_encrypted(prot) __pgprot_modify(prot, PROT_NS_SHARED, 0)
And maybe rewrite pgprot_device() as: #define __pgprot_device(prot) \ __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN) #define pgprot_device(prot) __pgprot_device(pgprot_decrypted(prot)) -- Catalin