From: Avi Kivity <avi@qumranet.com>
Date: Wed, 7 Mar 2007 11:05:38 +0000 (+0200)
Subject: KVM: Allow kernel to select size of mmap() buffer
X-Git-Tag: v2.6.22-rc1~1008^2~48
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=07c45a366d89f8eaec5d9890e810171b408f9a52;p=pandora-kernel.git

KVM: Allow kernel to select size of mmap() buffer

This allows us to store offsets in the kernel/user kvm_run area, and be
sure that userspace has them mapped.  As offsets can be outside the
kvm_run struct, userspace has no way of knowing how much to mmap.

Signed-off-by: Avi Kivity <avi@qumranet.com>
---

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index df85f5f65489..cba0b87c34e4 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -2436,7 +2436,7 @@ static long kvm_dev_ioctl(struct file *filp,
 			  unsigned int ioctl, unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
-	int r = -EINVAL;
+	long r = -EINVAL;
 
 	switch (ioctl) {
 	case KVM_GET_API_VERSION:
@@ -2478,6 +2478,12 @@ static long kvm_dev_ioctl(struct file *filp,
 		 */
 		r = 0;
 		break;
+	case KVM_GET_VCPU_MMAP_SIZE:
+		r = -EINVAL;
+		if (arg)
+			goto out;
+		r = PAGE_SIZE;
+		break;
 	default:
 		;
 	}
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