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authorMichael Riepe <michael@mr511.de>2006-12-22 01:05:36 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-22 08:55:46 -0800
commitbf591b24d07126143356058966d79423661f491f (patch)
tree1e075cd80f0bc6952d7b18411b05ee786900c3b9
parent2c264957105b7c248a456ba6602df667ae986550 (diff)
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[PATCH] KVM: Do not export unsupported msrs to userspace
Some msrs, such as MSR_STAR, are not available on all processors. Exporting them causes qemu to try to fetch them, which will fail. So, check all msrs for validity at module load time. Signed-off-by: Michael Riepe <michael@mr511.de> Signed-off-by: Avi Kivity <avi@qumranet.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--drivers/kvm/kvm_main.c27
1 files changed, 24 insertions, 3 deletions
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 4621b4ee674..bc2e6c19f85 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1417,6 +1417,9 @@ static int kvm_dev_ioctl_set_sregs(struct kvm *kvm, struct kvm_sregs *sregs)
/*
* List of msr numbers which we expose to userspace through KVM_GET_MSRS
* and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
+ *
+ * This list is modified at module load time to reflect the
+ * capabilities of the host cpu.
*/
static u32 msrs_to_save[] = {
MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
@@ -1427,6 +1430,22 @@ static u32 msrs_to_save[] = {
MSR_IA32_TIME_STAMP_COUNTER,
};
+static unsigned num_msrs_to_save;
+
+static __init void kvm_init_msr_list(void)
+{
+ u32 dummy[2];
+ unsigned i, j;
+
+ for (i = j = 0; i < ARRAY_SIZE(msrs_to_save); i++) {
+ if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0)
+ continue;
+ if (j < i)
+ msrs_to_save[j] = msrs_to_save[i];
+ j++;
+ }
+ num_msrs_to_save = j;
+}
/*
* Adapt set_msr() to msr_io()'s calling convention
@@ -1735,15 +1754,15 @@ static long kvm_dev_ioctl(struct file *filp,
if (copy_from_user(&msr_list, user_msr_list, sizeof msr_list))
goto out;
n = msr_list.nmsrs;
- msr_list.nmsrs = ARRAY_SIZE(msrs_to_save);
+ msr_list.nmsrs = num_msrs_to_save;
if (copy_to_user(user_msr_list, &msr_list, sizeof msr_list))
goto out;
r = -E2BIG;
- if (n < ARRAY_SIZE(msrs_to_save))
+ if (n < num_msrs_to_save)
goto out;
r = -EFAULT;
if (copy_to_user(user_msr_list->indices, &msrs_to_save,
- sizeof msrs_to_save))
+ num_msrs_to_save * sizeof(u32)))
goto out;
r = 0;
}
@@ -1894,6 +1913,8 @@ static __init int kvm_init(void)
kvm_init_debug();
+ kvm_init_msr_list();
+
if ((bad_page = alloc_page(GFP_KERNEL)) == NULL) {
r = -ENOMEM;
goto out;