linux-kernel - Re: [PATCH 07/11] treewide: Replace the use of mem_encrypt_active() with prot_guest

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Message-ID: <YQR+ffO92gMfGDbs@google.com>
Date:   Fri, 30 Jul 2021 22:34:37 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Tom Lendacky <thomas.lendacky@....com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-s390@...r.kernel.org,
        iommu@...ts.linux-foundation.org, kvm@...r.kernel.org,
        linux-efi@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-graphics-maintainer@...are.com,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        kexec@...ts.infradead.org, linux-fsdevel@...r.kernel.org,
        Borislav Petkov <bp@...en8.de>,
        Brijesh Singh <brijesh.singh@....com>,
        Joerg Roedel <joro@...tes.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Will Deacon <will@...nel.org>, Dave Young <dyoung@...hat.com>,
        Baoquan He <bhe@...hat.com>
Subject: Re: [PATCH 07/11] treewide: Replace the use of mem_encrypt_active()
 with prot_guest_has()

On Tue, Jul 27, 2021, Tom Lendacky wrote:
> @@ -451,7 +450,7 @@ void __init mem_encrypt_free_decrypted_mem(void)
>  	 * The unused memory range was mapped decrypted, change the encryption
>  	 * attribute from decrypted to encrypted before freeing it.
>  	 */
> -	if (mem_encrypt_active()) {
> +	if (sme_me_mask) {

Any reason this uses sme_me_mask?  The helper it calls, __set_memory_enc_dec(),
uses prot_guest_has(PATTR_MEM_ENCRYPT) so I assume it's available?

>  		r = set_memory_encrypted(vaddr, npages);
>  		if (r) {
>  			pr_warn("failed to free unused decrypted pages\n");