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Thu, 11 Jun 2020 10:10:09 +0100 From: Marc Zyngier To: Paolo Bonzini Subject: [PATCH 04/11] KVM: arm64: Stop save/restoring ACTLR_EL1 Date: Thu, 11 Jun 2020 10:09:49 +0100 Message-Id: <20200611090956.1537104-5-maz@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200611090956.1537104-1-maz@kernel.org> References: <20200611090956.1537104-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, alexandru.elisei@arm.com, ascull@google.com, james.morse@arm.com, mark.rutland@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200611_021011_630792_4B79DCA3 X-CRM114-Status: GOOD ( 12.21 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , kvm@vger.kernel.org, Suzuki K Poulose , James Morse , Andrew Scull , Alexandru Elisei , kvmarm@lists.cs.columbia.edu, Julien Thierry , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: James Morse KVM sets HCR_EL2.TACR via HCR_GUEST_FLAGS. This means ACTLR* accesses from the guest are always trapped, and always return the value in the sys_regs array. The guest can't change the value of these registers, so we are save restoring the reset value, which came from the host. Stop save/restoring this register. Keep the storage for this register in sys_regs[] as this is how the value is exposed to user-space, removing it would break migration. Signed-off-by: James Morse Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200529150656.7339-4-james.morse@arm.com --- arch/arm64/kvm/hyp/sysreg-sr.c | 2 -- arch/arm64/kvm/sys_regs.c | 2 -- 2 files changed, 4 deletions(-) diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c index 6d2df9fe0b5d..0d60e6ee96b2 100644 --- a/arch/arm64/kvm/hyp/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/sysreg-sr.c @@ -39,7 +39,6 @@ static void __hyp_text __sysreg_save_el1_state(struct kvm_cpu_context *ctxt) { ctxt->sys_regs[CSSELR_EL1] = read_sysreg(csselr_el1); ctxt->sys_regs[SCTLR_EL1] = read_sysreg_el1(SYS_SCTLR); - ctxt->sys_regs[ACTLR_EL1] = read_sysreg(actlr_el1); ctxt->sys_regs[CPACR_EL1] = read_sysreg_el1(SYS_CPACR); ctxt->sys_regs[TTBR0_EL1] = read_sysreg_el1(SYS_TTBR0); ctxt->sys_regs[TTBR1_EL1] = read_sysreg_el1(SYS_TTBR1); @@ -122,7 +121,6 @@ static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt) isb(); } - write_sysreg(ctxt->sys_regs[ACTLR_EL1], actlr_el1); write_sysreg_el1(ctxt->sys_regs[CPACR_EL1], SYS_CPACR); write_sysreg_el1(ctxt->sys_regs[TTBR0_EL1], SYS_TTBR0); write_sysreg_el1(ctxt->sys_regs[TTBR1_EL1], SYS_TTBR1); diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 12f8d57a3cb8..dfb966f3863a 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -78,7 +78,6 @@ static bool __vcpu_read_sys_reg_from_cpu(int reg, u64 *val) switch (reg) { case CSSELR_EL1: *val = read_sysreg_s(SYS_CSSELR_EL1); break; case SCTLR_EL1: *val = read_sysreg_s(SYS_SCTLR_EL12); break; - case ACTLR_EL1: *val = read_sysreg_s(SYS_ACTLR_EL1); break; case CPACR_EL1: *val = read_sysreg_s(SYS_CPACR_EL12); break; case TTBR0_EL1: *val = read_sysreg_s(SYS_TTBR0_EL12); break; case TTBR1_EL1: *val = read_sysreg_s(SYS_TTBR1_EL12); break; @@ -118,7 +117,6 @@ static bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg) switch (reg) { case CSSELR_EL1: write_sysreg_s(val, SYS_CSSELR_EL1); break; case SCTLR_EL1: write_sysreg_s(val, SYS_SCTLR_EL12); break; - case ACTLR_EL1: write_sysreg_s(val, SYS_ACTLR_EL1); break; case CPACR_EL1: write_sysreg_s(val, SYS_CPACR_EL12); break; case TTBR0_EL1: write_sysreg_s(val, SYS_TTBR0_EL12); break; case TTBR1_EL1: write_sysreg_s(val, SYS_TTBR1_EL12); break;