From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C81EA267B1B for ; Mon, 28 Apr 2025 11:57:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745841479; cv=none; b=odjXly3KGEV0ia2pvELs9GJNBqREMk7prWNPA74Xe1at50jqGHbTOjBVVYiBqsFUL6nc8qqKX9tJufrhSRtz9/s6khzzIghB2z8PFxLgzG7EFuZxYe6jWXLSuCYq6z+9atMBKKdXa/OC3dFX6qLKj1HbQxvTmXmcDu03DD/4Y60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745841479; c=relaxed/simple; bh=J4OW/u3Xz7UsUzctFrQjOAlfQdbWrTwt0nwQ7Hi3dTA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P/Dcl/NcQC2XutzcWjZOb++O1UXGteL3ECaF1fRExxZtiplfsAxFmLQ4ciNOrFTDYSu602+WPNPr/qXR3QqverXuTku/61a9oVom1RXBM9J5xlfQicQA7qoG8ShYC6llROrWMUg8XTxb3bA9JpjZpZqsl0xoH2aggIFjqINtM80= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fLKyy379; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fLKyy379" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85618C4CEE9; Mon, 28 Apr 2025 11:57:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745841479; bh=J4OW/u3Xz7UsUzctFrQjOAlfQdbWrTwt0nwQ7Hi3dTA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fLKyy379RuaJI1Is6RL1jFCp2X9Mke6ZHC2kzpLWQoQlK99tEc38l8M7+2udiSbfM xRhXzfdQJhgpcjVNK5pXdiCjInzAjSWDglZ6Cf44JLaSCver6XhlfKWOcPFZ/8wf1w WD80ZYUlF8US0YrwNUyo+w1shziFmWtmmF/e77yBGEUxffLnzk+VdBD6D1u7TwirWn ue/D9OjXfaYpqXUufdSTlOqsEeQ1zM3FR2iN2wz6hba+IgU1aalG+Yxlr2UEvyAw0W HWJD8Dm9ztEpkJyHXWsZ0rDyL9wl5RKhRZjtmJmbaqSuFj3iOFbprY6WZKFxsZ0x8+ 78Slv4i3qFqdg== From: "Aneesh Kumar K.V (Arm)" To: kvm@vger.kernel.org Cc: Suzuki K Poulose , Steven Price , Will Deacon , Julien Thierry , "Aneesh Kumar K.V (Arm)" Subject: [PATCH kvmtool v3 2/3] cpu: vmexit: Retry KVM_RUN ioctl on EINTR and EAGAIN Date: Mon, 28 Apr 2025 17:27:44 +0530 Message-ID: <20250428115745.70832-3-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250428115745.70832-1-aneesh.kumar@kernel.org> References: <20250428115745.70832-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When KVM_RUN fails with EINTR or EAGAIN, we should retry the ioctl without checking kvm_run->exit_reason. These errors don't indicate a valid VM exit, hence exit_reason may contain stale or undefined values. Signed-off-by: Aneesh Kumar K.V (Arm) --- include/kvm/kvm-cpu.h | 2 +- kvm-cpu.c | 17 ++++++++++++----- 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/include/kvm/kvm-cpu.h b/include/kvm/kvm-cpu.h index 8f76f8a1123a..72cbb86e6cef 100644 --- a/include/kvm/kvm-cpu.h +++ b/include/kvm/kvm-cpu.h @@ -16,7 +16,7 @@ void kvm_cpu__delete(struct kvm_cpu *vcpu); void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu); void kvm_cpu__setup_cpuid(struct kvm_cpu *vcpu); void kvm_cpu__enable_singlestep(struct kvm_cpu *vcpu); -void kvm_cpu__run(struct kvm_cpu *vcpu); +int kvm_cpu__run(struct kvm_cpu *vcpu); int kvm_cpu__start(struct kvm_cpu *cpu); bool kvm_cpu__handle_exit(struct kvm_cpu *vcpu); int kvm_cpu__get_endianness(struct kvm_cpu *vcpu); diff --git a/kvm-cpu.c b/kvm-cpu.c index 40041a22b3fe..7abbdcebf075 100644 --- a/kvm-cpu.c +++ b/kvm-cpu.c @@ -35,27 +35,32 @@ void kvm_cpu__enable_singlestep(struct kvm_cpu *vcpu) pr_warning("KVM_SET_GUEST_DEBUG failed"); } -void kvm_cpu__run(struct kvm_cpu *vcpu) +/* + * return value -1 if we need to call the kvm_cpu__run again without checking + * exit_reason. return value 0 results in taking action based on exit_reason. + */ +int kvm_cpu__run(struct kvm_cpu *vcpu) { int err; if (!vcpu->is_running) - return; + return -1; err = ioctl(vcpu->vcpu_fd, KVM_RUN, 0); if (err < 0) { switch (errno) { case EINTR: case EAGAIN: - return; + return -1; case EFAULT: if (vcpu->kvm_run->exit_reason == KVM_EXIT_MEMORY_FAULT) - return; + return 0; /* fallthrough */ default: die_perror("KVM_RUN failed"); } } + return 0; } static void kvm_cpu_signal_handler(int signum) @@ -179,7 +184,9 @@ int kvm_cpu__start(struct kvm_cpu *cpu) if (cpu->task) kvm_cpu__run_task(cpu); - kvm_cpu__run(cpu); + if (kvm_cpu__run(cpu) == -1) + /* retry without an exit_reason check */ + continue; switch (cpu->kvm_run->exit_reason) { case KVM_EXIT_UNKNOWN: -- 2.43.0