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[80.230.48.7]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48e6db0b08asm78949215e9.8.2026.05.11.02.04.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 May 2026 02:04:13 -0700 (PDT) Date: Mon, 11 May 2026 05:04:08 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: "David Hildenbrand (Arm)" , Jason Wang , Xuan Zhuo , Eugenio =?utf-8?B?UMOpcmV6?= , Muchun Song , Oscar Salvador , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Hugh Dickins , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , virtualization@lists.linux.dev, linux-mm@kvack.org, Andrea Arcangeli Subject: [PATCH resend v6 26/30] virtio_balloon: disable reporting zeroed optimization for confidential guests Message-ID: <77585f29352cb5fa235898db07e7a3fa04d4d04e.1778489843.git.mst@redhat.com> References: Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 4OArvZjLOtDnMan-12dbDZP2od5iA-gKKluaOf14CHw_1778490255 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In confidential computing environments (TDX, SEV-SNP), the host is untrusted and may lie about zeroing reported pages. Clear DEVICE_INIT_REPORTED in validate() so the guest does not skip re-zeroing based on hints from an untrusted device. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- drivers/virtio/virtio_balloon.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index e5d11782ce41..d1cdb904d60b 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -18,6 +18,7 @@ #include #include #include +#include /* * Balloon device works in 4K page units. So each page is pointed to by @@ -1190,6 +1191,8 @@ static int virtballoon_validate(struct virtio_device *vdev) !want_init_on_free()) __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED); + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) + __virtio_clear_bit(vdev, VIRTIO_BALLOON_F_DEVICE_INIT_REPORTED); __virtio_clear_bit(vdev, VIRTIO_F_ACCESS_PLATFORM); return 0; } -- MST