linux-kernel - Re: [PATCH v6 15/24] KVM: arm64: Support unaligned fixmap in the pKVM hyp

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Message-ID: <20250910124742.34185645@gandalf.local.home>
Date: Wed, 10 Sep 2025 12:47:42 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Vincent Donnefort <vdonnefort@...gle.com>
Cc: mhiramat@...nel.org, mathieu.desnoyers@...icios.com,
 linux-trace-kernel@...r.kernel.org, maz@...nel.org, oliver.upton@...ux.dev,
 joey.gouly@....com, suzuki.poulose@....com, yuzenghui@...wei.com,
 kvmarm@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
 jstultz@...gle.com, qperret@...gle.com, will@...nel.org,
 aneesh.kumar@...nel.org, kernel-team@...roid.com,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 15/24] KVM: arm64: Support unaligned fixmap in the
 pKVM hyp


Would be nice if the arm KVM folks could review the second part of this
patch series.

Vincent, I finished my review, and you can post a new version. But it would
still be good to get some input from the architecture folks.

-- Steve


On Thu, 21 Aug 2025 09:14:03 +0100
Vincent Donnefort <vdonnefort@...gle.com> wrote:

> Return the fixmap VA with the page offset, instead of the page base
> address. This allows to use hyp_fixmap_map() seamlessly regardless of
> the address alignment.
> 
> Signed-off-by: Vincent Donnefort <vdonnefort@...gle.com>
> 
> diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c
> index ae8391baebc3..75014dc7d82e 100644
> --- a/arch/arm64/kvm/hyp/nvhe/mm.c
> +++ b/arch/arm64/kvm/hyp/nvhe/mm.c
> @@ -239,7 +239,7 @@ static void *fixmap_map_slot(struct hyp_fixmap_slot *slot, phys_addr_t phys)
>  	WRITE_ONCE(*ptep, pte);
>  	dsb(ishst);
>  
> -	return (void *)slot->addr;
> +	return (void *)slot->addr + offset_in_page(phys);
>  }
>  
>  void *hyp_fixmap_map(phys_addr_t phys)