Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bf591b24 authored by Michael Riepe's avatar Michael Riepe Committed by Linus Torvalds
Browse files

[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: default avatarMichael Riepe <michael@mr511.de>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 2c264957

drivers/kvm/kvm_main.c

+24 −3
Original line number Diff line number Diff line
@@ -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;