The patch titled
KVM: Do not export unsupported msrs to userspace
has been added to the -mm tree. Its filename is
kvm-do-not-export-unsupported-msrs-to-userspace.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: KVM: Do not export unsupported msrs to userspace
From: Michael Riepe <michael@xxxxxxxx>
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@xxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/kvm/kvm_main.c | 27 ++++++++++++++++++++++++---
1 file changed, 24 insertions(+), 3 deletions(-)
diff -puN drivers/kvm/kvm_main.c~kvm-do-not-export-unsupported-msrs-to-userspace drivers/kvm/kvm_main.c
--- a/drivers/kvm/kvm_main.c~kvm-do-not-export-unsupported-msrs-to-userspace
+++ a/drivers/kvm/kvm_main.c
@@ -1417,6 +1417,9 @@ static int kvm_dev_ioctl_set_sregs(struc
/*
* 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 = 0;
+
+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 *f
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;
_
Patches currently in -mm which might be from michael@xxxxxxxx are
kvm-do-not-export-unsupported-msrs-to-userspace.patch
kvm-do-not-export-unsupported-msrs-to-userspace-tweak.patch
kvm-force-real-mode-cs-limit-to-64k.patch
kvm-handle-p5-mce-msrs.patch
-
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