linux-kernel - Re: [PATCH] KVM: arm64: Allow module-owned pages in host stage-2 range adjustment

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Message-ID: <86y0l2b7b4.wl-maz@kernel.org>
Date: Mon, 09 Feb 2026 09:22:07 +0000
From: Marc Zyngier <maz@...nel.org>
To: <kyle-jk.liao@...iatek.com>
Cc: Oliver Upton <oupton@...nel.org>,
	Joey
 Gouly <joey.gouly@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Quentin
 Perret <qperret@...gle.com>,
	Vincent Donnefort <vdonnefort@...gle.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	<kvmarm@...ts.linux.dev>,
	<linux-kernel@...r.kernel.org>,
	<linux-mediatek@...ts.infradead.org>,
	<wsd_upstream@...iatek.com>,
	<rock.yeh@...iatek.com>,
	<hungwen.chien@...iatek.com>
Subject: Re: [PATCH] KVM: arm64: Allow module-owned pages in host stage-2 range adjustment

On Mon, 09 Feb 2026 03:24:13 +0000,
<kyle-jk.liao@...iatek.com> wrote:
> 
> From: "kyle-jk.liao" <kyle-jk.liao@...iatek.com>
> 
> The host_stage2_adjust_range() function triggers a WARN_ON when
> encountering pages marked as both PKVM_NOPAGE and PKVM_MODULE_OWNED_PAGE.
> This occurs when load_unaligned_zeropad() accesses memory that crosses
> page boundaries, where one of the pages is module-owned.
> 
> Extend the check to accept pages with the PKVM_MODULE_OWNED_PAGE flag
> in addition to PKVM_NOPAGE, preventing spurious warnings during normal
> module memory access patterns.
> 
> Signed-off-by: kyle-jk.liao <kyle-jk.liao@...iatek.com>
> ---
>  arch/arm64/kvm/hyp/nvhe/mem_protect.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> index 49db32f3ddf7..baaabf4b5112 100644
> --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> @@ -495,6 +495,7 @@ static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range)
>  	u64 granule;
>  	s8 level;
>  	int ret;
> +	enum pkvm_page_state state;
>  
>  	hyp_assert_lock_held(&host_mmu.lock);
>  	ret = kvm_pgtable_get_leaf(&host_mmu.pgt, addr, &pte, &level);
> @@ -505,8 +506,9 @@ static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range)
>  		return -EAGAIN;
>  
>  	if (pte) {
> +		state = get_host_state(hyp_phys_to_page(addr));
>  		WARN_ON(addr_is_memory(addr) &&
> -			get_host_state(hyp_phys_to_page(addr)) != PKVM_NOPAGE);
> +			(state != PKVM_NOPAGE && state != (PKVM_NOPAGE | PKVM_MODULE_OWNED_PAGE)));
>  		return -EPERM;
>  	}
>  

None of that exists upstream.

	M.

-- 
Without deviation from the norm, progress is not possible.