From patchwork Wed Apr 16 13:43:25 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Yufeng X-Patchwork-Id: 14053980 Received: from cstnet.cn (smtp21.cstnet.cn [159.226.251.21]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3DDBC1DE4CA for ; Wed, 16 Apr 2025 13:44:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.21 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744811073; cv=none; b=lWVqQZep0t9r6QhctontFDvxSVQfSLPf5cJztfWf3LVyE34oCXVG6nizQPOAaSwg8OdJ8pGLCFulCxPtDwu3Q6183TV0pMzqYoyMguq8fqZZY7mDNwJFkR5XujjkubwMgwIcH+I/dlK7fVcOIJdpsnuNI5j+LfyC8b3cQgLbQjU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744811073; c=relaxed/simple; bh=IC3advjk3xHp7EJnY4XpggVm8Uowi0VulroBe8wf+UQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=cwRBecnhJ8XwRQq18uk8jTVJ/1Fpxbf1XrVZtZ58UPimYlSw0nMYxx0rtBF4zLcH92gy1bJiV/R/THnThzZhsqXgn6gDJN60/GFcGZFg8qcLdu4a9j022O9vRW8Mo2yIX3q9v4RSHttB2aZkPLkkKL9cKVso5Duk1ip9kda0F7U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iie.ac.cn; spf=pass smtp.mailfrom=iie.ac.cn; arc=none smtp.client-ip=159.226.251.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iie.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iie.ac.cn Received: from localhost.localdomain (unknown [159.226.95.28]) by APP-01 (Coremail) with SMTP id qwCowACHMQIatP9niEZKCQ--.14330S2; Wed, 16 Apr 2025 21:43:57 +0800 (CST) From: Chen Yufeng To: seanjc@google.com Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, kvm@vger.kernel.org, chenyufeng@iie.ac.cn Subject: [PATCH] kvm: x86: Don't report guest userspace emulation error to userspace in kvm_task_switch() Date: Wed, 16 Apr 2025 21:43:25 +0800 Message-ID: <20250416134326.1342-1-chenyufeng@iie.ac.cn> X-Mailer: git-send-email 2.43.0.windows.1 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: qwCowACHMQIatP9niEZKCQ--.14330S2 X-Coremail-Antispam: 1UD129KBjvJXoW7uFWfAF4fCFyrWF4Uur15Jwb_yoW8Gry5pr Z2k3s3ur1kJasYyayDKFWfWwn8Za4kGrnrGryDGay0qw45KasxXr4I93y5JF1fZws3Xa1f XF95XF1fCF1DAaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9j14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1I6r4UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8cxa n2IY04v7MxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4 AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE 17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMI IF0xvE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4l IxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvf C2KfnxnUUI43ZEXa7VUbGQ6JUUUUU== X-CM-SenderInfo: xfkh05xxih0wo6llvhldfou0/1tbiBgwOEmf-gV+fbAAAsj This patch prevents that emulation failures which result from emulating task switch for an L2-Guest results in being reported to userspace. Without this patch a malicious L2-Guest would be able to kill the L1 by triggering a race-condition between an vmexit and the task switch emulator. This patch is smiliar to commit fc3a9157d314 ("KVM: X86: Don't report L2 emulation failures to user-space") Fixes: 1051778f6e1e ("KVM: x86: Handle emulation failure directly in kvm_task_switch()") Signed-off-by: Chen Yufeng --- arch/x86/kvm/x86.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3712dde0bf9d..b22be88196ed 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11874,9 +11874,11 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index, */ if (ret || vcpu->mmio_needed) { vcpu->mmio_needed = false; - vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; - vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; - vcpu->run->internal.ndata = 0; + if (!is_guest_mode(vcpu)) { + vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION; + vcpu->run->internal.ndata = 0; + } return 0; }