From nobody Fri Dec 26 05:06:10 2025 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 9FF554691 for ; Wed, 10 Jan 2024 00:39:45 +0000 (UTC) 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="XSWtWN7f" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-dbdb46770d7so4527766276.1 for ; Tue, 09 Jan 2024 16:39:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1704847184; x=1705451984; 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=6xnKyEv4OBvotGnyOqTbS4nPA0NPUNoMw8n+LkAwHEU=; b=XSWtWN7fzQbbzIAWT1B2BF6Rik9aDdNQwqiBQYaglkEYF9/kL4ySWJKtEqxVcU0Q6h pHwuPqrAlH2dVU2o1GoOkk2E9GmumodNOpx7kAt0sC5LAizstjgCp95Fo9m+hEhOAKS9 J0YmrRRGwrgTrLZYWkhE7AbvXVD51ZaW6H+iL0OjbX2L91abrNhlS4TcU19J8VGra3we HKX1qpkn0nVmD9hqJqJNIqAUTrYJzuzkeU+dhe2D7vkyR4fN3ShQdAUEMOjFfo1ra313 RTGhtvCLyTQTwUCJtpa7qcLGkIrKjPLQVh2TLxtqk+0kQtrYN5+rKcfgFx8UcdtAhknj oV9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704847184; x=1705451984; 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=6xnKyEv4OBvotGnyOqTbS4nPA0NPUNoMw8n+LkAwHEU=; b=GD/HFCWUYbm91NuoRVzootRLquiyB0K/gW51tozUx01Dt3Mt555xrOY3B9vtQ9Uiiw 2NvrOBCK6UXP1gtyvuN3+0hyeLS0iVX9hbZ7nLhGjrHkUxPQLIUKt5ydpeinZBe4gBAN flTmYZtfl+Jj+zqz4bfUKh55yrIMWrCOTluMzSnj75St0CFX9DZ4J6zG19fxbdxz9Qe9 tJUJZ5DnNfAIkWVNUf4XxtWKJT8DIX6U6ZjcvxKZVCIksBU6V3sZgupTfnu1exOOLCWG ZBDd2i1r5CmG+sjbO7XL55kaflRgwZScwVS4uu+g4Ss2vvpU0GsamJZLxQXzD8qdH5ev ccPg== X-Gm-Message-State: AOJu0YyudBRb6dAY0X+VaZPYS045wtN/aVEwa2s9KPwdafUc/WJjIan7 mDbjPi2nbk/RQeckPdnARDXORcnyMgFqw0YPZA== X-Google-Smtp-Source: AGHT+IGJdgMga5DZLPUMl5FS/PauMfNNe4vf3zX11dmX3/7XA4baZSYAUHhTmPFHLa7ontbom+AG5NPk4tM= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:1348:b0:dbc:c697:63bd with SMTP id g8-20020a056902134800b00dbcc69763bdmr83934ybu.0.1704847184802; Tue, 09 Jan 2024 16:39:44 -0800 (PST) Reply-To: Sean Christopherson Date: Tue, 9 Jan 2024 16:39:36 -0800 In-Reply-To: <20240110003938.490206-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240110003938.490206-1-seanjc@google.com> X-Mailer: git-send-email 2.43.0.472.g3155946c3a-goog Message-ID: <20240110003938.490206-3-seanjc@google.com> Subject: [PATCH 2/4] KVM: x86: Rely solely on preempted_in_kernel flag for directed yield From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Like Xu Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Snapshot preempted_in_kernel using kvm_arch_vcpu_in_kernel() so that the flag is "accurate" (or rather, consistent and deterministic within KVM) for guest with protected state, and explicitly use preempted_in_kernel when checking if a vCPU was preempted in kernel mode instead of bouncing through kvm_arch_vcpu_in_kernel(). Drop the gnarly logic in kvm_arch_vcpu_in_kernel() that redirects to preempted_in_kernel if the target vCPU is not the "running", i.e. loaded, vCPU, as the only reason that code existed was for the directed yield case where KVM wants to check the CPL of a vCPU that may or may not be loaded on the current pCPU. Cc: Like Xu Signed-off-by: Sean Christopherson Reviewed-by: Yuan Yao --- arch/x86/kvm/x86.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 415509918c7f..77494f9c8d49 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5062,8 +5062,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) int idx; =20 if (vcpu->preempted) { - if (!vcpu->arch.guest_state_protected) - vcpu->arch.preempted_in_kernel =3D !static_call(kvm_x86_get_cpl)(vcpu); + vcpu->arch.preempted_in_kernel =3D kvm_arch_vcpu_in_kernel(vcpu); =20 /* * Take the srcu lock as memslots will be accessed to check the gfn @@ -13093,7 +13092,7 @@ bool kvm_arch_dy_has_pending_interrupt(struct kvm_v= cpu *vcpu) =20 bool kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu) { - return kvm_arch_vcpu_in_kernel(vcpu); + return vcpu->arch.preempted_in_kernel; } =20 bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu) @@ -13116,9 +13115,6 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu) if (vcpu->arch.guest_state_protected) return true; =20 - if (vcpu !=3D kvm_get_running_vcpu()) - return vcpu->arch.preempted_in_kernel; - return static_call(kvm_x86_get_cpl)(vcpu) =3D=3D 0; } =20 --=20 2.43.0.472.g3155946c3a-goog