Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932182AbbHQQLo (ORCPT ); Mon, 17 Aug 2015 12:11:44 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:38365 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932146AbbHQQLm (ORCPT ); Mon, 17 Aug 2015 12:11:42 -0400 Message-ID: <55D20790.1050100@linaro.org> Date: Mon, 17 Aug 2015 18:10:56 +0200 From: Eric Auger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: Marc Zyngier , Thomas Gleixner , Jason Cooper CC: Christoffer Dall , Jiang Liu , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/4] irqchip: GICv3: Convert to EOImode == 1 References: <1439454526-1185-1-git-send-email-marc.zyngier@arm.com> <1439454526-1185-2-git-send-email-marc.zyngier@arm.com> In-Reply-To: <1439454526-1185-2-git-send-email-marc.zyngier@arm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5776 Lines: 164 Hi Marc, On 08/13/2015 10:28 AM, Marc Zyngier wrote: > So far, GICv3 has been used in with EOImode == 0. The effect of this > mode is to perform the priority drop and the deactivation of the > interrupt at the same time. > > While this works perfectly for Linux (we only have a single priority), > it causes issues when an interrupt is forwarded to a guest, and when > we want the guest to perform the EOI itself. > > For this case, the GIC architecture provides EOImode == 1, where: > - A write to ICC_EOIR1_EL1 drops the priority of the interrupt and leaves > it active. Other interrupts at the same priority level can now be taken, > but the active interrupt cannot be taken again > - A write to ICC_DIR_EL1 marks the interrupt as inactive, meaning it can > now be taken again. > > This patch converts the driver to be able to use this new mode, depending > on whether or not the kernel can behave as a hypervisor. No feature change. > > Signed-off-by: Marc Zyngier > --- > drivers/irqchip/irq-gic-v3.c | 37 +++++++++++++++++++++++++++++++++---- > include/linux/irqchip/arm-gic-v3.h | 9 +++++++++ > 2 files changed, 42 insertions(+), 4 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c > index c52f7ba..61190fb 100644 > --- a/drivers/irqchip/irq-gic-v3.c > +++ b/drivers/irqchip/irq-gic-v3.c > @@ -30,6 +30,7 @@ > #include > #include > #include > +#include > > #include "irq-gic-common.h" > #include "irqchip.h" > @@ -50,6 +51,7 @@ struct gic_chip_data { > }; > > static struct gic_chip_data gic_data __read_mostly; > +static struct static_key supports_deactivate = STATIC_KEY_INIT_TRUE; > > #define gic_data_rdist() (this_cpu_ptr(gic_data.rdists.rdist)) > #define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base) > @@ -293,7 +295,14 @@ static int gic_irq_get_irqchip_state(struct irq_data *d, > > static void gic_eoi_irq(struct irq_data *d) > { > - gic_write_eoir(gic_irq(d)); > + if (static_key_true(&supports_deactivate)) { > + /* No need to deactivate an LPI */ > + if (gic_irq(d) >= 8192) > + return; > + gic_write_dir(gic_irq(d)); > + } else { > + gic_write_eoir(gic_irq(d)); > + } > } > > static int gic_set_type(struct irq_data *d, unsigned int type) > @@ -343,15 +352,24 @@ static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs > > if (likely(irqnr > 15 && irqnr < 1020) || irqnr >= 8192) { > int err; > + > + if (static_key_true(&supports_deactivate)) > + gic_write_eoir(irqnr); > + > err = handle_domain_irq(gic_data.domain, irqnr, regs); > if (err) { > WARN_ONCE(true, "Unexpected interrupt received!\n"); > - gic_write_eoir(irqnr); > + if (static_key_true(&supports_deactivate)) > + gic_write_dir(irqnr); shouldn't be needed to DIR the irq if LPI but is it harmful? Just because we don't do it on gic_eoi_irq ... Best Regards Eric > + else > + gic_write_eoir(irqnr); > } > continue; > } > if (irqnr < 16) { > gic_write_eoir(irqnr); > + if (static_key_true(&supports_deactivate)) > + gic_write_dir(irqnr); > #ifdef CONFIG_SMP > handle_IPI(irqnr, regs); > #else > @@ -451,8 +469,13 @@ static void gic_cpu_sys_reg_init(void) > /* Set priority mask register */ > gic_write_pmr(DEFAULT_PMR_VALUE); > > - /* EOI deactivates interrupt too (mode 0) */ > - gic_write_ctlr(ICC_CTLR_EL1_EOImode_drop_dir); > + if (static_key_true(&supports_deactivate)) { > + /* EOI drops priority only (mode 1) */ > + gic_write_ctlr(ICC_CTLR_EL1_EOImode_drop); > + } else { > + /* EOI deactivates interrupt too (mode 0) */ > + gic_write_ctlr(ICC_CTLR_EL1_EOImode_drop_dir); > + } > > /* ... and let's hit the road... */ > gic_write_grpen1(1); > @@ -820,6 +843,12 @@ static int __init gic_of_init(struct device_node *node, struct device_node *pare > if (of_property_read_u64(node, "redistributor-stride", &redist_stride)) > redist_stride = 0; > > + if (!is_hyp_mode_available()) > + static_key_slow_dec(&supports_deactivate); > + > + if (static_key_true(&supports_deactivate)) > + pr_info("GIC: Using split EOI/Deactivate mode\n"); > + > gic_data.dist_base = dist_base; > gic_data.redist_regions = rdist_regs; > gic_data.nr_redist_regions = nr_redist_regions; > diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h > index ffbc034..bc98832 100644 > --- a/include/linux/irqchip/arm-gic-v3.h > +++ b/include/linux/irqchip/arm-gic-v3.h > @@ -104,6 +104,8 @@ > #define GICR_SYNCR 0x00C0 > #define GICR_MOVLPIR 0x0100 > #define GICR_MOVALLR 0x0110 > +#define GICR_ISACTIVER GICD_ISACTIVER > +#define GICR_ICACTIVER GICD_ICACTIVER > #define GICR_IDREGS GICD_IDREGS > #define GICR_PIDR2 GICD_PIDR2 > > @@ -288,6 +290,7 @@ > #define ICH_VMCR_PMR_MASK (0xffUL << ICH_VMCR_PMR_SHIFT) > > #define ICC_EOIR1_EL1 sys_reg(3, 0, 12, 12, 1) > +#define ICC_DIR_EL1 sys_reg(3, 0, 12, 11, 1) > #define ICC_IAR1_EL1 sys_reg(3, 0, 12, 12, 0) > #define ICC_SGI1R_EL1 sys_reg(3, 0, 12, 11, 5) > #define ICC_PMR_EL1 sys_reg(3, 0, 4, 6, 0) > @@ -384,6 +387,12 @@ static inline void gic_write_eoir(u64 irq) > isb(); > } > > +static inline void gic_write_dir(u64 irq) > +{ > + asm volatile("msr_s " __stringify(ICC_DIR_EL1) ", %0" : : "r" (irq)); > + isb(); > +} > + > struct irq_domain; > int its_cpu_init(void); > int its_init(struct device_node *node, struct rdists *rdists, > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/