linux-kernel - [PATCH] kvm: Fixes lack of KVM_CAP_MANUAL_DIRTY_LOG

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Date:   Tue, 12 Jan 2021 17:29:42 +0800
From:   Kunkun Jiang <jiangkunkun@...wei.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC:     <wanghaibin.wang@...wei.com>, Keqian Zhu <zhukeqian1@...wei.com>
Subject: [PATCH] kvm: Fixes lack of KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 enabled check

The KVM_CLEAR_DIRTY_LOG ioctl lacks the check whether the capability
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT is enabled or not. This may cause
some problems if userspace calls the KVM_CLEAR_DIRTY_LOG ioctl, but
dose't enable this capability. So we'd better to add it.

Fixes: 2a31b9db15353 ("kvm: introduce manual dirty log reprotect")
Signed-off-by: Kunkun Jiang <jiangkunkun@...wei.com>
---
 virt/kvm/kvm_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fa9e3614d30e..8f5633d8a0e8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1602,6 +1602,9 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
 	unsigned long *dirty_bitmap_buffer;
 	bool flush;
 
+	if (!kvm->manual_dirty_log_protect)
+		return -EPERM;
+
 	/* Dirty ring tracking is exclusive to dirty log tracking */
 	if (kvm->dirty_ring_size)
 		return -ENXIO;
-- 
2.19.1