From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753524AbaHUQK6 (ORCPT ); Thu, 21 Aug 2014 12:10:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43213 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753400AbaHUQKy (ORCPT ); Thu, 21 Aug 2014 12:10:54 -0400 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , Gleb Natapov , Raghavendra KT , Vinod Chegu , Hui-Zhi Zhao , Christian Borntraeger , Lisa Mitchell Subject: [PATCH v3 6/7] KVM: VMX: runtime knobs for dynamic PLE window Date: Thu, 21 Aug 2014 18:08:10 +0200 Message-Id: <1408637291-18533-7-git-send-email-rkrcmar@redhat.com> In-Reply-To: <1408637291-18533-1-git-send-email-rkrcmar@redhat.com> References: <1408637291-18533-1-git-send-email-rkrcmar@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ple_window is updated on every vmentry, so there is no reason to have it read-only anymore. ple_window* weren't writable to prevent runtime overflow races; they are prevented by a seqlock. Signed-off-by: Radim Krčmář --- arch/x86/kvm/vmx.c | 46 +++++++++++++++++++++++++++++++++++++--------- 1 file changed, 37 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 273cbd5..1318232 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -132,24 +132,29 @@ module_param(nested, bool, S_IRUGO); #define KVM_VMX_DEFAULT_PLE_WINDOW_MAX \ INT_MAX / KVM_VMX_DEFAULT_PLE_WINDOW_GROW +static struct kernel_param_ops param_ops_ple_int; +#define param_check_ple_int(name, p) __param_check(name, p, int) + +static DEFINE_SEQLOCK(ple_window_seqlock); + static int ple_gap = KVM_VMX_DEFAULT_PLE_GAP; module_param(ple_gap, int, S_IRUGO); static int ple_window = KVM_VMX_DEFAULT_PLE_WINDOW; -module_param(ple_window, int, S_IRUGO); +module_param(ple_window, ple_int, S_IRUGO | S_IWUSR); /* Default doubles per-vcpu window every exit. */ static int ple_window_grow = KVM_VMX_DEFAULT_PLE_WINDOW_GROW; -module_param(ple_window_grow, int, S_IRUGO); +module_param(ple_window_grow, ple_int, S_IRUGO | S_IWUSR); /* Default resets per-vcpu window every exit to ple_window. */ static int ple_window_shrink = KVM_VMX_DEFAULT_PLE_WINDOW_SHRINK; -module_param(ple_window_shrink, int, S_IRUGO); +module_param(ple_window_shrink, int, S_IRUGO | S_IWUSR); /* Default is to compute the maximum so we can never overflow. */ static int ple_window_actual_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX; static int ple_window_max = KVM_VMX_DEFAULT_PLE_WINDOW_MAX; -module_param(ple_window_max, int, S_IRUGO); +module_param(ple_window_max, ple_int, S_IRUGO | S_IWUSR); extern const ulong vmx_return; @@ -5729,8 +5734,12 @@ static void grow_ple_window(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); int old = vmx->ple_window; + unsigned seq; - vmx->ple_window = __grow_ple_window(old); + do { + seq = read_seqbegin(&ple_window_seqlock); + vmx->ple_window = __grow_ple_window(old); + } while (read_seqretry(&ple_window_seqlock, seq)); trace_kvm_ple_window_grow(vcpu->vcpu_id, vmx->ple_window, old); } @@ -5739,9 +5748,13 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); int old = vmx->ple_window; + unsigned seq; - vmx->ple_window = __shrink_ple_window(old, - ple_window_shrink, ple_window); + do { + seq = read_seqbegin(&ple_window_seqlock); + vmx->ple_window = __shrink_ple_window(old, ple_window_shrink, + ple_window); + } while (read_seqretry(&ple_window_seqlock, seq)); trace_kvm_ple_window_shrink(vcpu->vcpu_id, vmx->ple_window, old); } @@ -5761,6 +5774,23 @@ static void update_ple_window_actual_max(void) ple_window_grow, INT_MIN); } +static int param_set_ple_int(const char *arg, const struct kernel_param *kp) +{ + int ret; + + write_seqlock(&ple_window_seqlock); + ret = param_set_int(arg, kp); + update_ple_window_actual_max(); + write_sequnlock(&ple_window_seqlock); + + return ret; +} + +static struct kernel_param_ops param_ops_ple_int = { + .set = param_set_ple_int, + .get = param_get_int, +}; + /* * Indicate a busy-waiting vcpu in spinlock. We do not enable the PAUSE * exiting, so only get here on cpu with PAUSE-Loop-Exiting. @@ -9164,8 +9194,6 @@ static int __init vmx_init(void) } else kvm_disable_tdp(); - update_ple_window_actual_max(); - return 0; out7: -- 2.1.0