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Date:   Wed, 2 Nov 2022 20:03:59 +0100
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Subject: Re: [PATCH] mm/memremap.c: map FS_DAX device memory as decrypted
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To:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        dan.j.williams@intel.com, thomas.lendacky@amd.com,
        pankaj.gupta@amd.com
References: <20221102160728.3184016-1-pankaj.gupta@amd.com>
From:   "Gupta, Pankaj" <pankaj.gupta@amd.com>
In-Reply-To: <20221102160728.3184016-1-pankaj.gupta@amd.com>
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+Cc Andrew [forgot to add earlier]

> virtio_pmem use devm_memremap_pages() to map the device memory.
> By default this memory is mapped as encrypted with SEV. Guest
> reboot changes the current encryption key and guest no longer
> properly decrypts the FSDAX device meta data.
> 
> Mark the corresponding device memory region for FSDAX devices
> (mapped with memremap_pages) as decrypted to retain the persistent
> memory property.
> 
> Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com>
> ---
>   mm/memremap.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/mm/memremap.c b/mm/memremap.c
> index 421bec3a29ee..08cbf54fe037 100644
> --- a/mm/memremap.c
> +++ b/mm/memremap.c
> @@ -335,6 +335,7 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
>   			WARN(1, "File system DAX not supported\n");
>   			return ERR_PTR(-EINVAL);
>   		}
> +		params.pgprot = pgprot_decrypted(params.pgprot);
>   		break;
>   	case MEMORY_DEVICE_GENERIC:
>   		break;