Re: [PATCH] arm64: clear_page() shouldn't use DC ZVA when DCZID_EL0.DZP == 1
From: Reiji Watanabe <hidden>
Date: 2021-10-27 01:37:00
On Tue, Oct 26, 2021 at 2:06 AM Catalin Marinas [off-list ref] wrote:
On Mon, Oct 25, 2021 at 08:48:44PM -0700, Reiji Watanabe wrote:quoted
Currently, clear_page() uses DC ZVA instruction unconditionally. But it should make sure that DCZID_EL0.DZP, which indicates whether or not use of DC ZVA instruction is prohibited, is zero when using the instruction. Use stp as memset does instead when DCZID_EL0.DZP == 1.For correctness, this is fine, but have you come across a system that has DZP == 1 (or hypervisor setting HCR_EL2.TDZ)?
We are thinking of setting HCR_EL2.TDZ considering live migration support between two systems with different DCZID_EL0.BS. Thanks, Reiji _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel