From nobody Fri Dec 19 14:41:52 2025 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 994B9213230 for ; Tue, 1 Apr 2025 16:43:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743525807; cv=none; b=P30ZQ37J2unvT4dRPJiSxzEWQmJJ4jhHD73XayBi9nz2OFyCbmTp1+PraDHgO8v6a4Z8nBe+2SVw/ZVW25Ts/aXjQfjyo66d9FalveA1QCAR2+1UjYmpyMLUQ93qfomXZAfH3uvrBCWpBP1Pt+ovt+qUJ6Eq9e6IfgcBIkHzmrQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743525807; c=relaxed/simple; bh=5iq6Ej0JukMZOt4v5A++8d64xSPyqQ5v5er7/1iuZW4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Wa3Jo+vUt0GU1ipq2PO9quXzc1i/qTqMHRZbrdMMQZHU6R/xHvavAmLqtCaCQp2HwGNH9n74F9fYVYmL/cOgkJCADK5KhiCR5Vvq7cjXw9OQ2mlpYUnDgczZ0Y3EyPJZjBalZHlySbili5tO5V8r6lmaeyswL+KLbEg9ZJkjjWo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=IB82jXoQ; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="IB82jXoQ" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2255ae39f8fso276975ad.0 for ; Tue, 01 Apr 2025 09:43:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1743525802; x=1744130602; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=/XYYrhooXHNQcqBoobC7D5bK0XS2jFQGb7UC9bcI9h8=; b=IB82jXoQ/BkQnpCN7Rnwso7yq0sh9Olsv/ISZOjrxCNXY38HN21itGuR8GTyHGf5QT elKTjYZKc0bXe7hovNqFTEKchRz5UlBPzDilS+eSSz4Ek6pGZ+j8pDbPHD7rU/xm2IOp FfFptLjn4aizDgbDhMESnlL8jF+KDt0ecpZnxYvi9AzUzt1XMMX/5oSc/UHa2owTPg/g 9jVjaJFdqd1DB7wZJHIg3/bY5u1INOUwXBLOlX+j7yuXxFNWOfK8uj53110xYeHxDJ+w iyv0WPoY+M0BnIZRVGN1LSrtD9FctfBHdKZXyOhcomhuWmiWK6wC7DhjuD5O94ELMmIY qjyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1743525802; x=1744130602; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=/XYYrhooXHNQcqBoobC7D5bK0XS2jFQGb7UC9bcI9h8=; b=D2ji8HemsJ/+jv/jsK4wmYIg9IvMfs4vCfZY+fYHIEYrAndeLIMROPd5h5H7/zgBGi RRPq/+KaJmhORj0mznWSP+YI74/q6jeMUSSrF28Ky9nMWETUKckkUhUtmFxYwfAQGXZo p9Jmiw3Cw5IzjsDyP8kk94JAW7h2r3CxTYSAD+hcyzKf46ezSQQdODSlqKnBpYRkcmdH FmqoEi87Z4EEqGpMFtYXzFzCsCSRVqjyMKK131vHcxj8sR67pyE4nuGJ33WiCnjv2LXw Ml5wz2vq5P7j4WddqHFJ+eSaXym1H4t1/At6HzjxiVcbk+CcIRVpKD120+zfaqzmPhkv NbBg== X-Gm-Message-State: AOJu0YyubQf35cp88tW9YP2mJAcoeAnNdYeTNOidRaa13TdGxkw961Zo lGzTvsgNfBypcqYcJrtZ4yG7uQZkvrXzF4SrcdmKk3NOfMHaU87f+wxIWDYqKiNmWUAKnrr0/31 RKw== X-Google-Smtp-Source: AGHT+IFy0IhgEaHcg00977nQlGMuEOMnb3oYwKlOFTc/u3M4G7iMNsSXATt5UTOpWjp44DoW3ZbtcVNrt4s= X-Received: from pfbfo6.prod.google.com ([2002:a05:6a00:6006:b0:736:3cd5:ba36]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:8186:b0:736:b400:b58f with SMTP id d2e1a72fcca58-739c3f771bcmr873231b3a.0.1743525801845; Tue, 01 Apr 2025 09:43:21 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 1 Apr 2025 09:34:44 -0700 In-Reply-To: <20250401163447.846608-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250401163447.846608-1-seanjc@google.com> X-Mailer: git-send-email 2.49.0.472.ge94155a9ec-goog Message-ID: <20250401163447.846608-6-seanjc@google.com> Subject: [PATCH v2 5/8] KVM: VMX: Process PIR using 64-bit accesses on 64-bit kernels From: Sean Christopherson To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Sean Christopherson , Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Jim Mattson Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Process the PIR at the natural kernel width, i.e. in 64-bit chunks on 64-bit kernels, so that the worst case of having a posted IRQ in each chunk of the vIRR only requires 4 loads and xchgs from/to the PIR, not 8. Deliberately use a "continue" to skip empty entries so that the code is a carbon copy of handle_pending_pir(), in anticipation of deduplicating KVM and posted MSI logic. Suggested-by: Jim Mattson Signed-off-by: Sean Christopherson --- arch/x86/kvm/lapic.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 893e7d06e0e6..e4f182ee9340 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -657,26 +657,32 @@ static u8 count_vectors(void *bitmap) =20 bool __kvm_apic_update_irr(unsigned long *pir, void *regs, int *max_irr) { - u32 *__pir =3D (void *)pir; + unsigned long pir_vals[NR_PIR_WORDS]; + u32 *__pir =3D (void *)pir_vals; u32 i, vec; - u32 pir_val, irr_val, prev_irr_val; + u32 irr_val, prev_irr_val; int max_updated_irr; =20 max_updated_irr =3D -1; *max_irr =3D -1; =20 + for (i =3D 0; i < NR_PIR_WORDS; i++) { + pir_vals[i] =3D READ_ONCE(pir[i]); + if (!pir_vals[i]) + continue; + + pir_vals[i] =3D xchg(&pir[i], 0); + } + for (i =3D vec =3D 0; i <=3D 7; i++, vec +=3D 32) { u32 *p_irr =3D (u32 *)(regs + APIC_IRR + i * 0x10); =20 irr_val =3D READ_ONCE(*p_irr); - pir_val =3D READ_ONCE(__pir[i]); - - if (pir_val) { - pir_val =3D xchg(&__pir[i], 0); =20 + if (__pir[i]) { prev_irr_val =3D irr_val; do { - irr_val =3D prev_irr_val | pir_val; + irr_val =3D prev_irr_val | __pir[i]; } while (prev_irr_val !=3D irr_val && !try_cmpxchg(p_irr, &prev_irr_val, irr_val)); =20 --=20 2.49.0.472.ge94155a9ec-goog