[PATCH v5 12/19] efi: arm64: Map Device with Prot Shared
Gavin Shan
gshan at redhat.com
Mon Sep 9 21:15:39 PDT 2024
On 8/19/24 11:19 PM, Steven Price wrote:
> From: Suzuki K Poulose <suzuki.poulose at arm.com>
>
> Device mappings need to be emualted by the VMM so must be mapped shared
> with the host.
>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> Signed-off-by: Steven Price <steven.price at arm.com>
> ---
> Changes since v4:
> * Reworked to use arm64_is_iomem_private() to decide whether the memory
> needs to be decrypted or not.
> ---
> arch/arm64/kernel/efi.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
> index 712718aed5dd..95f8e8bf07f8 100644
> --- a/arch/arm64/kernel/efi.c
> +++ b/arch/arm64/kernel/efi.c
> @@ -34,8 +34,16 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
> u64 attr = md->attribute;
> u32 type = md->type;
>
> - if (type == EFI_MEMORY_MAPPED_IO)
> - return PROT_DEVICE_nGnRE;
> + if (type == EFI_MEMORY_MAPPED_IO) {
> + pgprot_t prot = __pgprot(PROT_DEVICE_nGnRE);
> +
> + if (arm64_is_iomem_private(md->phys_addr,
> + md->num_pages << EFI_PAGE_SHIFT))
> + prot = pgprot_encrypted(prot);
> + else
> + prot = pgprot_decrypted(prot);
> + return pgprot_val(prot);
> + }
>
Question: the second parameter (@size) passed to arm64_is_iomem_private() covers the
whole region. In [PATCH v5 10/19] arm64: Override set_fixmap_io, the size has been
truncated to the granule size (4KB). They look inconsistent and I don't understand
the reason.
Thanks,
Gavin
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