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charset=us-ascii Content-Disposition: inline In-Reply-To: <20260921144847.501151-3-aneesh.kumar@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260922_092604_648476_E59E0E19 X-CRM114-Status: GOOD ( 14.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Sep 21, 2026 at 08:18:36PM +0530, Aneesh Kumar K.V (Arm) wrote: > +int alloc_cc_shared_pages_node(int nid, gfp_t gfp, > + size_t requested, struct cc_shared_pages *mem) > +{ > + struct cc_shared_layout layout; > + struct page *page; > + unsigned int order; > + bool zero = gfp & __GFP_ZERO; > + int ret; > + > + if (!mem) > + return -EINVAL; > + > + ret = cc_shared_calc_layout(requested, &layout); > + if (ret) > + return ret; > + > + order = get_order(layout.shared_size); > + if (order > MAX_PAGE_ORDER) > + return -EINVAL; > + > + /* > + * State transitions require a linear-map address and may modify memory. > + * Allocate from low memory and defer requested zeroing until afterwards. > + */ > + gfp &= ~(__GFP_HIGHMEM | __GFP_ZERO); > + if (nid == NUMA_NO_NODE) > + page = alloc_pages(gfp, order); > + else > + page = alloc_pages_node(nid, gfp, order); > + if (!page) > + return -ENOMEM; > + > + ret = cc_make_shared(page_address(page), layout.shared_size); > + if (ret) { > + if (!cc_make_private(page_address(page), layout.shared_size)) > + __free_pages(page, order); > + else > + pr_warn_ratelimited("leaking %zu bytes with uncertain shared state\n", > + layout.shared_size); > + return ret; > + } > + > + if (zero) > + memset(page_address(page), 0, layout.shared_size); Does the memset() post sharing logic work for pKVM as well? If nothing clears it, we have a small window where guest data is leaked to the host. Is there a case where we *do not* need the memory cleared? If not, maybe we can move the logic in the arch set_memory_decrypted(). -- Catalin