This is a note to let you know that I have just added a patch titled
MIPS: KVM: Fix ASID restoration logic
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt22.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From 9571c879cb5f6c0493304005df1af2e2a8e3ea45 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@xxxxxxxxxx>
Date: Wed, 11 Nov 2015 14:21:18 +0000
Subject: MIPS: KVM: Fix ASID restoration logic
commit 002374f371bd02df864cce1fe85d90dc5b292837 upstream.
ASID restoration on guest resume should determine the guest execution
mode based on the guest Status register rather than bit 30 of the guest
PC.
Fix the two places in locore.S that do this, loading the guest status
from the cop0 area. Note, this assembly is specific to the trap &
emulate implementation of KVM, so it doesn't need to check the
supervisor bit as that mode is not implemented in the guest.
Fixes: b680f70fc111 ("KVM/MIPS32: Entry point for trampolining to...")
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
[ luis: backported to 3.16:
- file rename: locore.S -> kvm_locore.S ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
arch/mips/kvm/kvm_locore.S | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/mips/kvm/kvm_locore.S b/arch/mips/kvm/kvm_locore.S
index 17376cd838e6..fc24acb3a837 100644
--- a/arch/mips/kvm/kvm_locore.S
+++ b/arch/mips/kvm/kvm_locore.S
@@ -159,9 +159,11 @@ FEXPORT(__kvm_mips_vcpu_run)
FEXPORT(__kvm_mips_load_asid)
/* Set the ASID for the Guest Kernel */
- INT_SLL t0, t0, 1 /* with kseg0 @ 0x40000000, kernel */
- /* addresses shift to 0x80000000 */
- bltz t0, 1f /* If kernel */
+ PTR_L t0, VCPU_COP0(k1)
+ LONG_L t0, COP0_STATUS(t0)
+ andi t0, KSU_USER | ST0_ERL | ST0_EXL
+ xori t0, KSU_USER
+ bnez t0, 1f /* If kernel */
INT_ADDIU t1, k1, VCPU_GUEST_KERNEL_ASID /* (BD) */
INT_ADDIU t1, k1, VCPU_GUEST_USER_ASID /* else user */
1:
@@ -438,9 +440,11 @@ __kvm_mips_return_to_guest:
mtc0 t0, CP0_EPC
/* Set the ASID for the Guest Kernel */
- INT_SLL t0, t0, 1 /* with kseg0 @ 0x40000000, kernel */
- /* addresses shift to 0x80000000 */
- bltz t0, 1f /* If kernel */
+ PTR_L t0, VCPU_COP0(k1)
+ LONG_L t0, COP0_STATUS(t0)
+ andi t0, KSU_USER | ST0_ERL | ST0_EXL
+ xori t0, KSU_USER
+ bnez t0, 1f /* If kernel */
INT_ADDIU t1, k1, VCPU_GUEST_KERNEL_ASID /* (BD) */
INT_ADDIU t1, k1, VCPU_GUEST_USER_ASID /* else user */
1:
