[PATCH 0/3] MIPS: KVM: Misc fixes

[PATCH 0/3] MIPS: KVM: Misc fixes

[James Hogan]

A few misc MIPS KVM fixes for issues that have been around since the
code was merged in v3.10.

James Hogan (3):
  MIPS: KVM: Fix ASID restoration logic
  MIPS: KVM: Fix CACHE immediate offset sign extension
  MIPS: KVM: Uninit VCPU in vcpu_create error path

 arch/mips/kvm/emulate.c |  2 +-
 arch/mips/kvm/locore.S  | 16 ++++++++++------
 arch/mips/kvm/mips.c    |  5 ++++-
 3 files changed, 15 insertions(+), 8 deletions(-)

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
Cc: <stable@vger.kernel.org>
-- 
2.4.10

[PATCH 1/3] MIPS: KVM: Fix ASID restoration logic

[James Hogan]

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
Cc: <stable@vger.kernel.org> # 3.10.x-
---
 arch/mips/kvm/locore.S | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/mips/kvm/locore.S b/arch/mips/kvm/locore.S
index c567240386a0..d1ee95a7f7dd 100644
--- a/arch/mips/kvm/locore.S
+++ b/arch/mips/kvm/locore.S
@@ -165,9 +165,11 @@ 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:
@@ -482,9 +484,11 @@ __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 2/3] MIPS: KVM: Fix CACHE immediate offset sign extension

[James Hogan]

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
Cc: <stable@vger.kernel.org> # 3.10.x-
---
 arch/mips/kvm/emulate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/kvm/emulate.c b/arch/mips/kvm/emulate.c
index d5fa3eaf39a1..41b1b090f56f 100644
--- a/arch/mips/kvm/emulate.c
+++ b/arch/mips/kvm/emulate.c
@@ -1581,7 +1581,7 @@ enum emulation_result kvm_mips_emulate_cache(uint32_t inst, uint32_t *opc,
 
 	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 3/3] MIPS: KVM: Uninit VCPU in vcpu_create error path

[James Hogan]

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
Cc: <stable@vger.kernel.org> # 3.10.x-
---
 arch/mips/kvm/mips.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 49ff3bfc007e..b9b803facdbf 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -279,7 +279,7 @@ 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_debug("Allocated %d bytes for KVM Exception Handlers @ %p\n",
 		  ALIGN(size, PAGE_SIZE), gebase);
@@ -343,6 +343,9 @@ 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 0/3] MIPS: KVM: Misc fixes

[Paolo Bonzini]

On 11/11/2015 15:21, James Hogan wrote:
> A few misc MIPS KVM fixes for issues that have been around since the
> code was merged in v3.10.
> 
> James Hogan (3):
>   MIPS: KVM: Fix ASID restoration logic
>   MIPS: KVM: Fix CACHE immediate offset sign extension
>   MIPS: KVM: Uninit VCPU in vcpu_create error path
> 
>  arch/mips/kvm/emulate.c |  2 +-
>  arch/mips/kvm/locore.S  | 16 ++++++++++------
>  arch/mips/kvm/mips.c    |  5 ++++-
>  3 files changed, 15 insertions(+), 8 deletions(-)
> 
> 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
> Cc: <stable@vger.kernel.org>
> 

Thanks, these will have to wait after the end of the merge window.

Paolo

Re: [PATCH 0/3] MIPS: KVM: Misc fixes

[James Hogan]

[-- Attachment #1: Type: text/plain, Size: 1065 bytes --]

Hi Paolo,

On Wed, Nov 11, 2015 at 03:43:14PM +0100, Paolo Bonzini wrote:
> On 11/11/2015 15:21, James Hogan wrote:
> > A few misc MIPS KVM fixes for issues that have been around since the
> > code was merged in v3.10.
> > 
> > James Hogan (3):
> >   MIPS: KVM: Fix ASID restoration logic
> >   MIPS: KVM: Fix CACHE immediate offset sign extension
> >   MIPS: KVM: Uninit VCPU in vcpu_create error path
> > 
> >  arch/mips/kvm/emulate.c |  2 +-
> >  arch/mips/kvm/locore.S  | 16 ++++++++++------
> >  arch/mips/kvm/mips.c    |  5 ++++-
> >  3 files changed, 15 insertions(+), 8 deletions(-)
> > 
> > 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
> > Cc: <stable@vger.kernel.org>
> > 
> 
> Thanks, these will have to wait after the end of the merge window.

Okay, no problem. As long as they can make v4.4.

For the record do you prefer not to receive patches during merge window?

Thanks
James

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [PATCH 0/3] MIPS: KVM: Misc fixes

[Paolo Bonzini]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256



On 11/11/2015 15:57, James Hogan wrote:
> Okay, no problem. As long as they can make v4.4.
> 
> For the record do you prefer not to receive patches during merge 
> window?

It's okay, at worst I won't process them for a few days or weeks.

Paolo
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2

iQEcBAEBCAAGBQJWQ1fWAAoJEL/70l94x66D5mEIAJbKuP0oRsfMVhZGDlonqzOp
+ugEDNWAzC8tQas2joei0tBtmsFMKY+9NXbFUUthcE0Tn4TbfBi5rRpOfE7B+ekV
Y6sec+vp0AsplpQtNI3OdU8jrZqMYkWUK6ZBdOJrpdPzBzfmFkXuMdimLomhdlVl
8r6Vh6la7RohEJWxXBAaGEzgGqIQ25H+Xw/FNHo3Pk2ZPhI2EgusSlMby6w087kQ
nht5LSVn92Jvx7CNCsqAEhccO/a6XYiRXfW+nFCa/Z1DUvYoezgyXl7jWvyGwKj5
9y73jwIYop63B+KcEDTWZ6gKu2GDrT+TQod+IlWoWDk58PdQjxI1BNcqS+QMFlc=
=VHcV
-----END PGP SIGNATURE-----