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From: Jinyu Tang <jinyu.tang@linux.dev>
To: SeungJu Cheon <suunj1331@gmail.com>
Cc: anup@brainfault.org, atish.patra@linux.dev, tjytimi@163.com,
	inochiama@gmail.com, pjw@kernel.org, palmer@dabbelt.com,
	aou@eecs.berkeley.edu, alex@ghiti.fr, andrew.jones@linux.dev,
	pbonzini@redhat.com, seanjc@google.com,
	kvm-riscv@lists.infradead.org, kvm@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org, sashiko-bot@kernel.org
Subject: Re: [PATCH] KVM: riscv: Only fast-path dirty-log write faults on host-writable leaves
Date: Fri, 23 Oct 2026 19:57:47 +0800	[thread overview]
Message-ID: <20261023115747.2545223-1-jinyu.tang@linux.dev> (raw)
In-Reply-To: <20261017030927.345454-1-suunj1331@gmail.com>

On Sat, Oct 17, 2026 at 12:09:26PM +0900, SeungJu Cheon wrote:
> +		/* Let the slow path handle host-side write protection and CoW. */
> +		if (!(pte_val(old_pte) & KVM_GSTAGE_PTE_HOST_WRITABLE)) {
> +			ret = false;
> +			break;
> +		}

Thanks for fixing this.
Tested on QEMU 10.2.1 with a private memfd mapping and dirty logging.
A guest read followed by a write corrupts the shared backing without
this fix; and with it, CoW occurs and the backing stays unchanged.

Reviewed-by: Jinyu Tang <jinyu.tang@linux.dev>

Thanks,
Jinyu

      parent reply	other threads:[~2026-10-23 11:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-17  3:09 [PATCH] KVM: riscv: Only fast-path dirty-log write faults on host-writable leaves SeungJu Cheon
2026-10-17  3:27 ` sashiko-bot
2026-10-23 11:57 ` Jinyu Tang [this message]

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