Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753314Ab3IJPaR (ORCPT ); Tue, 10 Sep 2013 11:30:17 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:17400 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752992Ab3IJPaJ (ORCPT ); Tue, 10 Sep 2013 11:30:09 -0400 From: Boris Ostrovsky To: xen-devel@lists.xen.org Cc: konrad.wilk@oracle.com, david.vrabel@citrix.com, JBeulich@suse.com, linux-kernel@vger.kernel.org, Boris Ostrovsky Subject: [PATCH v1 5/5] xen/PMU: Cache MSR accesses during interrupt handling Date: Tue, 10 Sep 2013 11:31:50 -0400 Message-Id: <1378827110-4192-6-git-send-email-boris.ostrovsky@oracle.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1378827110-4192-1-git-send-email-boris.ostrovsky@oracle.com> References: <1378827110-4192-1-git-send-email-boris.ostrovsky@oracle.com> X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2079 Lines: 64 Avoid trapping to hypervisor on each MSR access during interrupt handling. Instead, use cached MSR values provided in shared xenpmu_data by Xen. When handling is completed, flush the registers to hypervisor who will load them into HW. Signed-off-by: Boris Ostrovsky --- arch/x86/xen/pmu.c | 15 ++++++++++++++- include/xen/interface/xenpmu.h | 1 + 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c index d8b059b..bdd7c4a 100644 --- a/arch/x86/xen/pmu.c +++ b/arch/x86/xen/pmu.c @@ -345,14 +345,27 @@ static void xen_convert_regs(struct cpu_user_regs *xen_regs, irqreturn_t xen_pmu_irq_handler(int irq, void *dev_id) { - int ret = IRQ_NONE; + int err, ret = IRQ_NONE; struct pt_regs regs; struct xenpmu_data *xenpmu_data = per_cpu(xenpmu_shared, smp_processor_id()); + /* + * While handling the interrupt MSR accesses will be cached + * in PMU context + */ + xenpmu_data->pmu_flags |= PMU_CACHED; xen_convert_regs(&xenpmu_data->regs, ®s); if (x86_pmu.handle_irq(®s)) ret = IRQ_HANDLED; + xenpmu_data->pmu_flags &= ~PMU_CACHED; + + /* Write out cached context to HW */ + err = HYPERVISOR_xenpmu_op(XENPMU_flush, NULL); + if (err) { + WARN(1, "%s failed hypercall, err: %d\n", __func__, err); + return IRQ_NONE; + } return ret; } diff --git a/include/xen/interface/xenpmu.h b/include/xen/interface/xenpmu.h index 16fe1ab..ec0e802 100644 --- a/include/xen/interface/xenpmu.h +++ b/include/xen/interface/xenpmu.h @@ -16,6 +16,7 @@ #define XENPMU_init 4 #define XENPMU_finish 5 #define XENPMU_lvtpc_set 6 +#define XENPMU_flush 7 /* Write cached MSR values to HW */ /* Parameter structure for HYPERVISOR_xenpmu_op call */ struct xenpmu_params { -- 1.8.1.4 -- 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/