[PATCH backport v3.10 1/4] MIPS: KVM: Fix ASID restoration logic

[PATCH backport v3.10 1/4] MIPS: KVM: Fix ASID restoration logic

[James Hogan]

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@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 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 920b63210806..34c35f0e3290 100644
--- a/arch/mips/kvm/kvm_locore.S
+++ b/arch/mips/kvm/kvm_locore.S
@@ -156,9 +156,11 @@ FEXPORT(__kvm_mips_vcpu_run)
 
 FEXPORT(__kvm_mips_load_asid)
     /* Set the ASID for the Guest Kernel */
-    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 */
 	addiu       t1, k1, VCPU_GUEST_KERNEL_ASID  /* (BD)  */
     addiu       t1, k1, VCPU_GUEST_USER_ASID    /* else user */
 1:
@@ -442,9 +444,11 @@ __kvm_mips_return_to_guest:
 	mtc0		t0, CP0_EPC
 
     /* Set the ASID for the Guest Kernel */
-    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 */
 	addiu       t1, k1, VCPU_GUEST_KERNEL_ASID  /* (BD)  */
     addiu       t1, k1, VCPU_GUEST_USER_ASID    /* else user */
 1:
-- 
2.4.10

[PATCH backport v3.12..v3.14 2/4] MIPS: KVM: Fix ASID restoration logic

[James Hogan]

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@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 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 03a2db58b22d..ba5ce99c021d 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:
-- 
2.4.10

[PATCH backport v3.10..v3.14 3/4] MIPS: KVM: Fix CACHE immediate offset sign extension

[James Hogan]

commit c5c2a3b998f1ff5a586f9d37e154070b8d550d17 upstream.

The immediate field of the CACHE instruction is signed, so ensure that
it gets sign extended by casting it to an int16_t rather than just
masking the low 16 bits.

Fixes: e685c689f3a8 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 arch/mips/kvm/kvm_mips_emul.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c
index c76f297b7149..33085819cd89 100644
--- a/arch/mips/kvm/kvm_mips_emul.c
+++ b/arch/mips/kvm/kvm_mips_emul.c
@@ -935,7 +935,7 @@ kvm_mips_emulate_cache(uint32_t inst, uint32_t *opc, uint32_t cause,
 
 	base = (inst >> 21) & 0x1f;
 	op_inst = (inst >> 16) & 0x1f;
-	offset = inst & 0xffff;
+	offset = (int16_t)inst;
 	cache = (inst >> 16) & 0x3;
 	op = (inst >> 18) & 0x7;
 
-- 
2.4.10

[PATCH backport v3.10..v3.14 4/4] MIPS: KVM: Uninit VCPU in vcpu_create error path

[James Hogan]

commit 585bb8f9a5e592f2ce7abbe5ed3112d5438d2754 upstream.

If either of the memory allocations in kvm_arch_vcpu_create() fail, the
vcpu which has been allocated and kvm_vcpu_init'd doesn't get uninit'd
in the error handling path. Add a call to kvm_vcpu_uninit() to fix this.

Fixes: 669e846e6c4e ("KVM/MIPS32: MIPS arch specific APIs for KVM")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
---
 arch/mips/kvm/kvm_mips.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kvm/kvm_mips.c b/arch/mips/kvm/kvm_mips.c
index 2cb24788a8a6..7e7de1f2b8ed 100644
--- a/arch/mips/kvm/kvm_mips.c
+++ b/arch/mips/kvm/kvm_mips.c
@@ -312,7 +312,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 
 	if (!gebase) {
 		err = -ENOMEM;
-		goto out_free_cpu;
+		goto out_uninit_cpu;
 	}
 	kvm_info("Allocated %d bytes for KVM Exception Handlers @ %p\n",
 		 ALIGN(size, PAGE_SIZE), gebase);
@@ -372,6 +372,9 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 out_free_gebase:
 	kfree(gebase);
 
+out_uninit_cpu:
+	kvm_vcpu_uninit(vcpu);
+
 out_free_cpu:
 	kfree(vcpu);
 
-- 
2.4.10

Re: [PATCH backport v3.12..v3.14 2/4] MIPS: KVM: Fix ASID restoration logic

[Jiri Slaby]

On 12/11/2015, 06:06 PM, James Hogan wrote:
> commit 002374f371bd02df864cce1fe85d90dc5b292837 upstream.

Applied 2/4 -- 4/4 to 3.12. Thanks.

-- 
js
suse labs