Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964789AbbHFRna (ORCPT ); Thu, 6 Aug 2015 13:43:30 -0400 Received: from foss.arm.com ([217.140.101.70]:39621 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753526AbbHFRn2 (ORCPT ); Thu, 6 Aug 2015 13:43:28 -0400 Date: Thu, 6 Aug 2015 18:43:24 +0100 From: Catalin Marinas To: Marc Zyngier Cc: Will Deacon , Christoffer Dall , kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Subject: Re: [PATCH 00/13] arm64: Virtualization Host Extension support Message-ID: <20150806174324.GD17691@e104818-lin.cambridge.arm.com> References: <1436372356-30410-1-git-send-email-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1436372356-30410-1-git-send-email-marc.zyngier@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3624 Lines: 92 On Wed, Jul 08, 2015 at 05:19:03PM +0100, Marc Zyngier wrote: > Marc Zyngier (13): > arm/arm64: Add new is_kernel_in_hyp_mode predicate > arm64: Allow the arch timer to use the HYP timer > arm64: Add ARM64_HAS_VIRT_HOST_EXTN feature > arm64: KVM: skip HYP setup when already running in HYP > arm64: KVM: VHE: macroize VTCR_EL2 setup > arm64: KVM: VHE: Patch out kern_hyp_va > arm64: KVM: VHE: Patch out use of HVC > arm64: KVM: VHE: Preserve VHE config in world switch > arm64: KVM: VHE: Add alternatives for VHE-enabled world-switch > arm64: Add support for running Linux in EL2 mode > arm64: Panic when VHE and non VHE CPUs coexist > arm64: KVM: Split sysreg save/restore > arm64: KVM: VHE: Early interrupt handling Do we need to do anything with the debug code? Do we have any hardware breakpoints/watchpoints targeting kernel space (kgdb doesn't seem to support this)? If a breakpoint target is EL1, I don't think we trigger it when running in the EL2/VHE mode, in which case we need a different DBGBCR.{HMC,SSC,PMC} combination - {1,11,00}. Another random untested patch below but we need to get Will to remember the code he wrote (and the VHE implications): diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h index 52b484b6aa1a..197af39a5ffb 100644 --- a/arch/arm64/include/asm/hw_breakpoint.h +++ b/arch/arm64/include/asm/hw_breakpoint.h @@ -34,8 +34,12 @@ struct arch_hw_breakpoint { static inline u32 encode_ctrl_reg(struct arch_hw_breakpoint_ctrl ctrl) { - return (ctrl.len << 5) | (ctrl.type << 3) | (ctrl.privilege << 1) | + u32 reg = (ctrl.len << 5) | (ctrl.type << 3) | (ctrl.privilege << 1) | ctrl.enabled; + /* set HMC and SSC when debug target is EL2 */ + if (ctrl.privilege == AARCH64_BREAKPOINT_EL2) + reg |= (3 << 14) | (1 << 13); + return reg } static inline void decode_ctrl_reg(u32 reg, @@ -59,6 +63,7 @@ static inline void decode_ctrl_reg(u32 reg, #define AARCH64_ESR_ACCESS_MASK (1 << 6) /* Privilege Levels */ +#define AARCH64_BREAKPOINT_EL2 0 #define AARCH64_BREAKPOINT_EL1 1 #define AARCH64_BREAKPOINT_EL0 2 diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index 7a1a5da6c8c1..77866839d1e8 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -162,6 +162,7 @@ static enum debug_el debug_exception_level(int privilege) case AARCH64_BREAKPOINT_EL0: return DBG_ACTIVE_EL0; case AARCH64_BREAKPOINT_EL1: + case AARCH64_BREAKPOINT_EL2: return DBG_ACTIVE_EL1; default: pr_warning("invalid breakpoint privilege level %d\n", privilege); @@ -456,7 +457,8 @@ static int arch_build_bp_info(struct perf_event *bp) * that would complicate the stepping code. */ if (arch_check_bp_in_kernelspace(bp)) - info->ctrl.privilege = AARCH64_BREAKPOINT_EL1; + info->ctrl.privilege = is_kernel_in_hyp_mode() ? + AARCH64_BREAKPOINT_EL2 : AARCH64_BREAKPOINT_EL1; else info->ctrl.privilege = AARCH64_BREAKPOINT_EL0; @@ -526,7 +528,7 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp) * Disallow per-task kernel breakpoints since these would * complicate the stepping code. */ - if (info->ctrl.privilege == AARCH64_BREAKPOINT_EL1 && bp->hw.target) + if (info->ctrl.privilege != AARCH64_BREAKPOINT_EL0 && bp->hw.target) return -EINVAL; return 0; -- Catalin -- 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/