[PATCH v5 00/34] arm/arm64: KVM: Rework the hyp-stub API

[PATCH v5 00/34] arm/arm64: KVM: Rework the hyp-stub API

[Marc Zyngier]

As noticed by RMK in this thread[1], the hyp-stub API on 32bit ARM
could do with some TLC (it cannot perform a soft-restart at HYP, and
has holes in the hyp-stub support in a number of places). In general,
it would be desirable for the 32bit behaviour to align on 64bit, if
only to ease maintenance.

This series implements the following:
- Add HVC_[GS]ET_VECTORS and HVC_SOFT_RESTART to the 32bit code
- Add HVC_RESET_VECTORS to both arm and arm64, removing the need for
  __hyp_reset_vectors
- Implement add the stub entry points in the KVM init code, which
  didn't implement any so far
- Convert the HYP code to use the init code stubs directly
- Some general cleanup as a result of these changes (which includes
  killing HVC_GET_VECTORS)
- Add some API documentation that covers the above

Patches 14 to 16 would be better squashed into 12 and 13, but I've
kept them separate so that I can take the blame for everything I've
broken.

I've tested this on arm (Cubietruck, Jetson TK1) and arm64 (Seattle),
both as host and guest. Keerthy has been kind enough to test the 32bit
code on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473472.html

* From v4:
  - Added a standard return value on stub hypercall failure
  - Zero r0/x0 on successful hypercall
  - Make 32bit ARM resistant to kvm_reboot while executing a guest
  - Update documentation to reflect the calling convention expectations
  - Added Acks from Catalin
  - Rebased on 4.11-rc5

* From v3:
  - Reworked the way we save/restore lr on arm64, making it EL2's job
  in a consistent way (these are the three initial patches)
  - Collected RBs, TBs and Acks from James, Keerthy and Russell
  - Rebased on 4.11-rc3

* From v2:
  - Kill HVC_GET_VECTORS and the corresponding __hyp_get_vectors

* From v1:
  - Fixed some glaring bugs (reported by Ard and James)
  - Tidy up stub vector export on 32bit (Ard)
  - Nicer VA/PA conversion on 32bit (Ard)
  - Updated cpu_v7_reset documentation
  - Cleaned up HYP reset on PM events
  - Minor stub documentation update

Marc Zyngier (32):
  arm64: hyp-stub: Stop pointlessly clobbering lr
  arm64: KVM: Move lr save/restore to do_el2_call
  arm64: hyp-stub: Don't save lr in the EL1 code
  arm64: hyp-stub: Define a return value for failed stub calls
  arm64: hyp-stub: Update documentation in asm/virt.h
  arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
  arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init
    code
  arm64: KVM: Implement HVC_GET_VECTORS in the init code
  arm64: KVM: Allow the main HYP code to use the init hyp stub
    implementation
  arm64: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors
  arm64: KVM: Implement HVC_SOFT_RESTART in the init code
  ARM: KVM: Convert KVM to use HVC_GET_VECTORS
  ARM: Update cpu_v7_reset documentation
  ARM: hyp-stub: Use r1 for the soft-restart address
  ARM: Expose the VA/IDMAP offset
  ARM: hyp-stub: Define a return value for failed stub calls
  ARM: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
  ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code
  ARM: KVM: Implement HVC_GET_VECTORS in the init code
  ARM: KVM: Allow the main HYP code to use the init hyp stub
    implementation
  ARM: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors
  ARM: KVM: Implement HVC_SOFT_RESTART in the init code
  ARM: KVM: Gracefully handle hyp-stubs being restored from under our
    feet
  arm/arm64: KVM: Use __hyp_reset_vectors() directly
  arm/arm64: KVM: Remove kvm_get_idmap_start
  arm/arm64: KVM: Use HVC_RESET_VECTORS to reinit HYP mode
  ARM: decompressor: Remove __hyp_get_vectors usage
  ARM: hyp-stub/KVM: Kill __hyp_get_vectors
  arm64: hyp-stub/KVM: Kill __hyp_get_vectors
  arm64: hyp-stub: Zero x0 on successful stub handling
  ARM: hyp-stub: Zero r0 on successful stub handling
  arm/arm64: Add hyp-stub API documentation

Russell King (2):
  ARM: hyp-stub: improve ABI
  ARM: soft-reboot into same mode that we entered the kernel

 Documentation/virtual/kvm/arm/hyp-abi.txt | 53 +++++++++++++++++++++++++++++++
 arch/arm/boot/compressed/head.S           | 12 ++++++-
 arch/arm/include/asm/kvm_asm.h            |  4 +--
 arch/arm/include/asm/kvm_host.h           |  6 ----
 arch/arm/include/asm/kvm_mmu.h            |  1 -
 arch/arm/include/asm/proc-fns.h           |  4 +--
 arch/arm/include/asm/virt.h               | 14 +++++++-
 arch/arm/kernel/hyp-stub.S                | 41 +++++++++++++++++++-----
 arch/arm/kernel/reboot.c                  |  7 ++--
 arch/arm/kvm/arm.c                        | 25 ++++++---------
 arch/arm/kvm/handle_exit.c                |  8 +++++
 arch/arm/kvm/hyp/hyp-entry.S              | 29 ++++++++++++++---
 arch/arm/kvm/init.S                       | 51 ++++++++++++++++++++++++-----
 arch/arm/kvm/interrupts.S                 |  4 ---
 arch/arm/kvm/mmu.c                        |  5 ---
 arch/arm/mm/mmu.c                         |  5 +++
 arch/arm/mm/proc-v7.S                     | 15 ++++++---
 arch/arm64/include/asm/kvm_asm.h          |  3 +-
 arch/arm64/include/asm/kvm_host.h         |  7 ----
 arch/arm64/include/asm/kvm_mmu.h          |  1 -
 arch/arm64/include/asm/virt.h             | 31 ++++++++++++------
 arch/arm64/kernel/hyp-stub.S              | 38 ++++++++--------------
 arch/arm64/kvm/hyp-init.S                 | 46 +++++++++++++++++++++------
 arch/arm64/kvm/hyp.S                      |  5 +--
 arch/arm64/kvm/hyp/hyp-entry.S            | 43 ++++++++++++-------------
 25 files changed, 312 insertions(+), 146 deletions(-)
 create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt

-- 
2.11.0

[PATCH v5 00/34] arm/arm64: KVM: Rework the hyp-stub API

[Marc Zyngier]

As noticed by RMK in this thread[1], the hyp-stub API on 32bit ARM
could do with some TLC (it cannot perform a soft-restart at HYP, and
has holes in the hyp-stub support in a number of places). In general,
it would be desirable for the 32bit behaviour to align on 64bit, if
only to ease maintenance.

This series implements the following:
- Add HVC_[GS]ET_VECTORS and HVC_SOFT_RESTART to the 32bit code
- Add HVC_RESET_VECTORS to both arm and arm64, removing the need for
  __hyp_reset_vectors
- Implement add the stub entry points in the KVM init code, which
  didn't implement any so far
- Convert the HYP code to use the init code stubs directly
- Some general cleanup as a result of these changes (which includes
  killing HVC_GET_VECTORS)
- Add some API documentation that covers the above

Patches 14 to 16 would be better squashed into 12 and 13, but I've
kept them separate so that I can take the blame for everything I've
broken.

I've tested this on arm (Cubietruck, Jetson TK1) and arm64 (Seattle),
both as host and guest. Keerthy has been kind enough to test the 32bit
code on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473472.html

* From v4:
  - Added a standard return value on stub hypercall failure
  - Zero r0/x0 on successful hypercall
  - Make 32bit ARM resistant to kvm_reboot while executing a guest
  - Update documentation to reflect the calling convention expectations
  - Added Acks from Catalin
  - Rebased on 4.11-rc5

* From v3:
  - Reworked the way we save/restore lr on arm64, making it EL2's job
  in a consistent way (these are the three initial patches)
  - Collected RBs, TBs and Acks from James, Keerthy and Russell
  - Rebased on 4.11-rc3

* From v2:
  - Kill HVC_GET_VECTORS and the corresponding __hyp_get_vectors

* From v1:
  - Fixed some glaring bugs (reported by Ard and James)
  - Tidy up stub vector export on 32bit (Ard)
  - Nicer VA/PA conversion on 32bit (Ard)
  - Updated cpu_v7_reset documentation
  - Cleaned up HYP reset on PM events
  - Minor stub documentation update

Marc Zyngier (32):
  arm64: hyp-stub: Stop pointlessly clobbering lr
  arm64: KVM: Move lr save/restore to do_el2_call
  arm64: hyp-stub: Don't save lr in the EL1 code
  arm64: hyp-stub: Define a return value for failed stub calls
  arm64: hyp-stub: Update documentation in asm/virt.h
  arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
  arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init
    code
  arm64: KVM: Implement HVC_GET_VECTORS in the init code
  arm64: KVM: Allow the main HYP code to use the init hyp stub
    implementation
  arm64: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors
  arm64: KVM: Implement HVC_SOFT_RESTART in the init code
  ARM: KVM: Convert KVM to use HVC_GET_VECTORS
  ARM: Update cpu_v7_reset documentation
  ARM: hyp-stub: Use r1 for the soft-restart address
  ARM: Expose the VA/IDMAP offset
  ARM: hyp-stub: Define a return value for failed stub calls
  ARM: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
  ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code
  ARM: KVM: Implement HVC_GET_VECTORS in the init code
  ARM: KVM: Allow the main HYP code to use the init hyp stub
    implementation
  ARM: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors
  ARM: KVM: Implement HVC_SOFT_RESTART in the init code
  ARM: KVM: Gracefully handle hyp-stubs being restored from under our
    feet
  arm/arm64: KVM: Use __hyp_reset_vectors() directly
  arm/arm64: KVM: Remove kvm_get_idmap_start
  arm/arm64: KVM: Use HVC_RESET_VECTORS to reinit HYP mode
  ARM: decompressor: Remove __hyp_get_vectors usage
  ARM: hyp-stub/KVM: Kill __hyp_get_vectors
  arm64: hyp-stub/KVM: Kill __hyp_get_vectors
  arm64: hyp-stub: Zero x0 on successful stub handling
  ARM: hyp-stub: Zero r0 on successful stub handling
  arm/arm64: Add hyp-stub API documentation

Russell King (2):
  ARM: hyp-stub: improve ABI
  ARM: soft-reboot into same mode that we entered the kernel

 Documentation/virtual/kvm/arm/hyp-abi.txt | 53 +++++++++++++++++++++++++++++++
 arch/arm/boot/compressed/head.S           | 12 ++++++-
 arch/arm/include/asm/kvm_asm.h            |  4 +--
 arch/arm/include/asm/kvm_host.h           |  6 ----
 arch/arm/include/asm/kvm_mmu.h            |  1 -
 arch/arm/include/asm/proc-fns.h           |  4 +--
 arch/arm/include/asm/virt.h               | 14 +++++++-
 arch/arm/kernel/hyp-stub.S                | 41 +++++++++++++++++++-----
 arch/arm/kernel/reboot.c                  |  7 ++--
 arch/arm/kvm/arm.c                        | 25 ++++++---------
 arch/arm/kvm/handle_exit.c                |  8 +++++
 arch/arm/kvm/hyp/hyp-entry.S              | 29 ++++++++++++++---
 arch/arm/kvm/init.S                       | 51 ++++++++++++++++++++++++-----
 arch/arm/kvm/interrupts.S                 |  4 ---
 arch/arm/kvm/mmu.c                        |  5 ---
 arch/arm/mm/mmu.c                         |  5 +++
 arch/arm/mm/proc-v7.S                     | 15 ++++++---
 arch/arm64/include/asm/kvm_asm.h          |  3 +-
 arch/arm64/include/asm/kvm_host.h         |  7 ----
 arch/arm64/include/asm/kvm_mmu.h          |  1 -
 arch/arm64/include/asm/virt.h             | 31 ++++++++++++------
 arch/arm64/kernel/hyp-stub.S              | 38 ++++++++--------------
 arch/arm64/kvm/hyp-init.S                 | 46 +++++++++++++++++++++------
 arch/arm64/kvm/hyp.S                      |  5 +--
 arch/arm64/kvm/hyp/hyp-entry.S            | 43 ++++++++++++-------------
 25 files changed, 312 insertions(+), 146 deletions(-)
 create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt

-- 
2.11.0

[PATCH v5 01/34] arm64: hyp-stub: Stop pointlessly clobbering lr

[Marc Zyngier]

When entering the kernel hyp stub, we check whether or not we've
made it here through an HVC instruction, clobbering lr (aka x30)
in the process.

This is completely pointless, as HVC is the only way to get here
(all traps to EL2 are disabled, no interrupt override is applied).

So let's remove this bit of code whose only point is to corrupt
a valuable register.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kernel/hyp-stub.S | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d3b5f75e652e..e4215ad06930 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -55,12 +55,6 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	mrs	x30, esr_el2
-	lsr	x30, x30, #ESR_ELx_EC_SHIFT
-
-	cmp	x30, #ESR_ELx_EC_HVC64
-	b.ne	9f				// Not an HVC trap
-
 	cmp	x0, #HVC_GET_VECTORS
 	b.ne	1f
 	mrs	x0, vbar_el2
-- 
2.11.0

[PATCH v5 01/34] arm64: hyp-stub: Stop pointlessly clobbering lr

[Marc Zyngier]

When entering the kernel hyp stub, we check whether or not we've
made it here through an HVC instruction, clobbering lr (aka x30)
in the process.

This is completely pointless, as HVC is the only way to get here
(all traps to EL2 are disabled, no interrupt override is applied).

So let's remove this bit of code whose only point is to corrupt
a valuable register.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kernel/hyp-stub.S | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d3b5f75e652e..e4215ad06930 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -55,12 +55,6 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	mrs	x30, esr_el2
-	lsr	x30, x30, #ESR_ELx_EC_SHIFT
-
-	cmp	x30, #ESR_ELx_EC_HVC64
-	b.ne	9f				// Not an HVC trap
-
 	cmp	x0, #HVC_GET_VECTORS
 	b.ne	1f
 	mrs	x0, vbar_el2
-- 
2.11.0

[PATCH v5 02/34] arm64: KVM: Move lr save/restore to do_el2_call

[Marc Zyngier]

At the moment, we only save/restore lr if on VHE, as we rely only
the EL1 code to have preserved it in the non-VHE case.

As we're about to get rid of the latter, let's move the save/restore
code to the do_el2_call macro, unifying both code paths.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp.S           | 3 ---
 arch/arm64/kvm/hyp/hyp-entry.S | 4 ++--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 2726635dceba..f6f20b58d65a 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -38,13 +38,10 @@
  * A function pointer with a value less than 0xfff has a special meaning,
  * and is used to implement __hyp_get_vectors in the same way as in
  * arch/arm64/kernel/hyp_stub.S.
- * HVC behaves as a 'bl' call and will clobber lr.
  */
 ENTRY(__kvm_call_hyp)
 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
-	str     lr, [sp, #-16]!
 	hvc	#0
-	ldr     lr, [sp], #16
 	ret
 alternative_else_nop_endif
 	b	__vhe_hyp_call
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 5e9052f087f2..d8ef788646c6 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -32,17 +32,17 @@
 	 * Shuffle the parameters before calling the function
 	 * pointed to in x0. Assumes parameters in x[1,2,3].
 	 */
+	str	lr, [sp, #-16]!
 	mov	lr, x0
 	mov	x0, x1
 	mov	x1, x2
 	mov	x2, x3
 	blr	lr
+	ldr	lr, [sp], #16
 .endm
 
 ENTRY(__vhe_hyp_call)
-	str	lr, [sp, #-16]!
 	do_el2_call
-	ldr	lr, [sp], #16
 	/*
 	 * We used to rely on having an exception return to get
 	 * an implicit isb. In the E2H case, we don't have it anymore.
-- 
2.11.0

[PATCH v5 02/34] arm64: KVM: Move lr save/restore to do_el2_call

[Marc Zyngier]

At the moment, we only save/restore lr if on VHE, as we rely only
the EL1 code to have preserved it in the non-VHE case.

As we're about to get rid of the latter, let's move the save/restore
code to the do_el2_call macro, unifying both code paths.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp.S           | 3 ---
 arch/arm64/kvm/hyp/hyp-entry.S | 4 ++--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 2726635dceba..f6f20b58d65a 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -38,13 +38,10 @@
  * A function pointer with a value less than 0xfff has a special meaning,
  * and is used to implement __hyp_get_vectors in the same way as in
  * arch/arm64/kernel/hyp_stub.S.
- * HVC behaves as a 'bl' call and will clobber lr.
  */
 ENTRY(__kvm_call_hyp)
 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
-	str     lr, [sp, #-16]!
 	hvc	#0
-	ldr     lr, [sp], #16
 	ret
 alternative_else_nop_endif
 	b	__vhe_hyp_call
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 5e9052f087f2..d8ef788646c6 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -32,17 +32,17 @@
 	 * Shuffle the parameters before calling the function
 	 * pointed to in x0. Assumes parameters in x[1,2,3].
 	 */
+	str	lr, [sp, #-16]!
 	mov	lr, x0
 	mov	x0, x1
 	mov	x1, x2
 	mov	x2, x3
 	blr	lr
+	ldr	lr, [sp], #16
 .endm
 
 ENTRY(__vhe_hyp_call)
-	str	lr, [sp, #-16]!
 	do_el2_call
-	ldr	lr, [sp], #16
 	/*
 	 * We used to rely on having an exception return to get
 	 * an implicit isb. In the E2H case, we don't have it anymore.
-- 
2.11.0

[PATCH v5 03/34] arm64: hyp-stub: Don't save lr in the EL1 code

[Marc Zyngier]

The EL2 code is not corrupting lr anymore, so don't bother preserving
it in the EL1 trampoline code.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kernel/hyp-stub.S | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index e4215ad06930..193dfb25ce2f 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -116,18 +116,14 @@ ENDPROC(\label)
  */
 
 ENTRY(__hyp_get_vectors)
-	str	lr, [sp, #-16]!
 	mov	x0, #HVC_GET_VECTORS
 	hvc	#0
-	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_get_vectors)
 
 ENTRY(__hyp_set_vectors)
-	str	lr, [sp, #-16]!
 	mov	x1, x0
 	mov	x0, #HVC_SET_VECTORS
 	hvc	#0
-	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_set_vectors)
-- 
2.11.0

[PATCH v5 03/34] arm64: hyp-stub: Don't save lr in the EL1 code

[Marc Zyngier]

The EL2 code is not corrupting lr anymore, so don't bother preserving
it in the EL1 trampoline code.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kernel/hyp-stub.S | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index e4215ad06930..193dfb25ce2f 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -116,18 +116,14 @@ ENDPROC(\label)
  */
 
 ENTRY(__hyp_get_vectors)
-	str	lr, [sp, #-16]!
 	mov	x0, #HVC_GET_VECTORS
 	hvc	#0
-	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_get_vectors)
 
 ENTRY(__hyp_set_vectors)
-	str	lr, [sp, #-16]!
 	mov	x1, x0
 	mov	x0, #HVC_SET_VECTORS
 	hvc	#0
-	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_set_vectors)
-- 
2.11.0

[PATCH v5 04/34] arm64: hyp-stub: Define a return value for failed stub calls

[Marc Zyngier]

Define a standard return value to be returned when a hyp stub
call fails, and make KVM use it for ARM_EXCEPTION_HYP_GONE
(instead of using a KVM-specific value).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/kvm_asm.h | 2 +-
 arch/arm64/include/asm/virt.h    | 3 +++
 arch/arm64/kernel/hyp-stub.S     | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index ec3553eb9349..1769380a8fc0 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -28,7 +28,7 @@
 #define ARM_EXCEPTION_EL1_SERROR  1
 #define ARM_EXCEPTION_TRAP	  2
 /* The hyp-stub will return this for any kvm_call_hyp() call */
-#define ARM_EXCEPTION_HYP_GONE	  3
+#define ARM_EXCEPTION_HYP_GONE	  HVC_STUB_ERR
 
 #define KVM_ARM64_DEBUG_DIRTY_SHIFT	0
 #define KVM_ARM64_DEBUG_DIRTY		(1 << KVM_ARM64_DEBUG_DIRTY_SHIFT)
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 439f6b5d31f6..1466d14c664d 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -39,6 +39,9 @@
  */
 #define HVC_SOFT_RESTART 2
 
+/* Error returned when an invalid stub number is passed into x0 */
+#define HVC_STUB_ERR	0xbadca11
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 193dfb25ce2f..f53e8b84cd3a 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -74,7 +74,7 @@ el1_sync:
 	br	x4				// no return
 
 	/* Someone called kvm_call_hyp() against the hyp-stub... */
-3:	mov	x0, #ARM_EXCEPTION_HYP_GONE
+3:	ldr	x0, =HVC_STUB_ERR
 
 9:	eret
 ENDPROC(el1_sync)
-- 
2.11.0

[PATCH v5 04/34] arm64: hyp-stub: Define a return value for failed stub calls

[Marc Zyngier]

Define a standard return value to be returned when a hyp stub
call fails, and make KVM use it for ARM_EXCEPTION_HYP_GONE
(instead of using a KVM-specific value).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/kvm_asm.h | 2 +-
 arch/arm64/include/asm/virt.h    | 3 +++
 arch/arm64/kernel/hyp-stub.S     | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index ec3553eb9349..1769380a8fc0 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -28,7 +28,7 @@
 #define ARM_EXCEPTION_EL1_SERROR  1
 #define ARM_EXCEPTION_TRAP	  2
 /* The hyp-stub will return this for any kvm_call_hyp() call */
-#define ARM_EXCEPTION_HYP_GONE	  3
+#define ARM_EXCEPTION_HYP_GONE	  HVC_STUB_ERR
 
 #define KVM_ARM64_DEBUG_DIRTY_SHIFT	0
 #define KVM_ARM64_DEBUG_DIRTY		(1 << KVM_ARM64_DEBUG_DIRTY_SHIFT)
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 439f6b5d31f6..1466d14c664d 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -39,6 +39,9 @@
  */
 #define HVC_SOFT_RESTART 2
 
+/* Error returned when an invalid stub number is passed into x0 */
+#define HVC_STUB_ERR	0xbadca11
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 193dfb25ce2f..f53e8b84cd3a 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -74,7 +74,7 @@ el1_sync:
 	br	x4				// no return
 
 	/* Someone called kvm_call_hyp() against the hyp-stub... */
-3:	mov	x0, #ARM_EXCEPTION_HYP_GONE
+3:	ldr	x0, =HVC_STUB_ERR
 
 9:	eret
 ENDPROC(el1_sync)
-- 
2.11.0

[PATCH v5 05/34] arm64: hyp-stub: Update documentation in asm/virt.h

[Marc Zyngier]

Comments in asm/virt.h are slightly out of date, so let's align
them with the new behaviour of the code.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 1466d14c664d..1569c3a0d794 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -19,9 +19,14 @@
 #define __ASM__VIRT_H
 
 /*
- * The arm64 hcall implementation uses x0 to specify the hcall type. A value
- * less than 0xfff indicates a special hcall, such as get/set vector.
- * Any other value is used as a pointer to the function to call.
+ * The arm64 hcall implementation uses x0 to specify the hcall
+ * number. A value less than HVC_STUB_HCALL_NR indicates a special
+ * hcall, such as set vector. Any other value is handled in a
+ * hypervisor specific way.
+ *
+ * The hypercall is allowed to clobber any of the caller-saved
+ * registers (x0-x18), so it is advisable to use it through the
+ * indirection of a function call (as implemented in hyp-stub.S).
  */
 
 /* HVC_GET_VECTORS - Return the value of the vbar_el2 register. */
-- 
2.11.0

[PATCH v5 05/34] arm64: hyp-stub: Update documentation in asm/virt.h

[Marc Zyngier]

Comments in asm/virt.h are slightly out of date, so let's align
them with the new behaviour of the code.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 1466d14c664d..1569c3a0d794 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -19,9 +19,14 @@
 #define __ASM__VIRT_H
 
 /*
- * The arm64 hcall implementation uses x0 to specify the hcall type. A value
- * less than 0xfff indicates a special hcall, such as get/set vector.
- * Any other value is used as a pointer to the function to call.
+ * The arm64 hcall implementation uses x0 to specify the hcall
+ * number. A value less than HVC_STUB_HCALL_NR indicates a special
+ * hcall, such as set vector. Any other value is handled in a
+ * hypervisor specific way.
+ *
+ * The hypercall is allowed to clobber any of the caller-saved
+ * registers (x0-x18), so it is advisable to use it through the
+ * indirection of a function call (as implemented in hyp-stub.S).
  */
 
 /* HVC_GET_VECTORS - Return the value of the vbar_el2 register. */
-- 
2.11.0

[PATCH v5 06/34] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

Let's define a new stub hypercall that resets the HYP configuration
to its default: hyp-stub vectors, and MMU disabled.

Of course, for the hyp-stub itself, this is a trivial no-op.
Hypervisors will have a bit more work to do.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h |  9 +++++++++
 arch/arm64/kernel/hyp-stub.S  | 11 ++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 1569c3a0d794..435514c52b0f 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -44,6 +44,14 @@
  */
 #define HVC_SOFT_RESTART 2
 
+/*
+ * HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
+ */
+#define HVC_RESET_VECTORS 3
+
+/* Max number of HYP stub hypercalls */
+#define HVC_STUB_HCALL_NR 4
+
 /* Error returned when an invalid stub number is passed into x0 */
 #define HVC_STUB_ERR	0xbadca11
 
@@ -70,6 +78,7 @@ extern u32 __boot_cpu_mode[2];
 
 void __hyp_set_vectors(phys_addr_t phys_vector_base);
 phys_addr_t __hyp_get_vectors(void);
+void __hyp_reset_vectors(void);
 
 /* Reports the availability of HYP mode */
 static inline bool is_hyp_mode_available(void)
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index f53e8b84cd3a..8226fd90f73c 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -73,8 +73,11 @@ el1_sync:
 	mov	x1, x3
 	br	x4				// no return
 
+3:	cmp	x0, #HVC_RESET_VECTORS
+	beq	9f				// Nothing to reset!
+
 	/* Someone called kvm_call_hyp() against the hyp-stub... */
-3:	ldr	x0, =HVC_STUB_ERR
+	ldr	x0, =HVC_STUB_ERR
 
 9:	eret
 ENDPROC(el1_sync)
@@ -127,3 +130,9 @@ ENTRY(__hyp_set_vectors)
 	hvc	#0
 	ret
 ENDPROC(__hyp_set_vectors)
+
+ENTRY(__hyp_reset_vectors)
+	mov	x0, #HVC_RESET_VECTORS
+	hvc	#0
+	ret
+ENDPROC(__hyp_reset_vectors)
-- 
2.11.0

[PATCH v5 06/34] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

Let's define a new stub hypercall that resets the HYP configuration
to its default: hyp-stub vectors, and MMU disabled.

Of course, for the hyp-stub itself, this is a trivial no-op.
Hypervisors will have a bit more work to do.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h |  9 +++++++++
 arch/arm64/kernel/hyp-stub.S  | 11 ++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 1569c3a0d794..435514c52b0f 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -44,6 +44,14 @@
  */
 #define HVC_SOFT_RESTART 2
 
+/*
+ * HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
+ */
+#define HVC_RESET_VECTORS 3
+
+/* Max number of HYP stub hypercalls */
+#define HVC_STUB_HCALL_NR 4
+
 /* Error returned when an invalid stub number is passed into x0 */
 #define HVC_STUB_ERR	0xbadca11
 
@@ -70,6 +78,7 @@ extern u32 __boot_cpu_mode[2];
 
 void __hyp_set_vectors(phys_addr_t phys_vector_base);
 phys_addr_t __hyp_get_vectors(void);
+void __hyp_reset_vectors(void);
 
 /* Reports the availability of HYP mode */
 static inline bool is_hyp_mode_available(void)
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index f53e8b84cd3a..8226fd90f73c 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -73,8 +73,11 @@ el1_sync:
 	mov	x1, x3
 	br	x4				// no return
 
+3:	cmp	x0, #HVC_RESET_VECTORS
+	beq	9f				// Nothing to reset!
+
 	/* Someone called kvm_call_hyp() against the hyp-stub... */
-3:	ldr	x0, =HVC_STUB_ERR
+	ldr	x0, =HVC_STUB_ERR
 
 9:	eret
 ENDPROC(el1_sync)
@@ -127,3 +130,9 @@ ENTRY(__hyp_set_vectors)
 	hvc	#0
 	ret
 ENDPROC(__hyp_set_vectors)
+
+ENTRY(__hyp_reset_vectors)
+	mov	x0, #HVC_RESET_VECTORS
+	hvc	#0
+	ret
+ENDPROC(__hyp_reset_vectors)
-- 
2.11.0

[PATCH v5 07/34] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code

[Marc Zyngier]

In order to restore HYP mode to its original condition, KVM currently
implements __kvm_hyp_reset(). As we're moving towards a hyp-stub
defined API, it becomes necessary to implement HVC_RESET_VECTORS.

This patch adds the HVC_RESET_VECTORS hypercall to the KVM init
code, which so far lacked any form of hypercall support.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 6b29d3d9e1f2..5e39ad53bcae 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -22,6 +22,7 @@
 #include <asm/kvm_mmu.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/sysreg.h>
+#include <asm/virt.h>
 
 	.text
 	.pushsection	.hyp.idmap.text, "ax"
@@ -58,6 +59,9 @@ __invalid:
 	 * x2: HYP vectors
 	 */
 __do_hyp_init:
+	/* Check for a stub HVC call */
+	cmp	x0, #HVC_STUB_HCALL_NR
+	b.lo	__kvm_handle_stub_hvc
 
 	msr	ttbr0_el2, x0
 
@@ -119,6 +123,9 @@ __do_hyp_init:
 	eret
 ENDPROC(__kvm_hyp_init)
 
+ENTRY(__kvm_handle_stub_hvc)
+	cmp	x0, #HVC_RESET_VECTORS
+	b.ne	1f
 	/*
 	 * Reset kvm back to the hyp stub.
 	 */
@@ -133,9 +140,15 @@ ENTRY(__kvm_hyp_reset)
 	/* Install stub vectors */
 	adr_l	x0, __hyp_stub_vectors
 	msr	vbar_el2, x0
+	b	exit
 
+1:	/* Bad stub call */
+	ldr	x0, =HVC_STUB_ERR
+
+exit:
 	eret
 ENDPROC(__kvm_hyp_reset)
+ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
 
-- 
2.11.0

[PATCH v5 07/34] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code

[Marc Zyngier]

In order to restore HYP mode to its original condition, KVM currently
implements __kvm_hyp_reset(). As we're moving towards a hyp-stub
defined API, it becomes necessary to implement HVC_RESET_VECTORS.

This patch adds the HVC_RESET_VECTORS hypercall to the KVM init
code, which so far lacked any form of hypercall support.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 6b29d3d9e1f2..5e39ad53bcae 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -22,6 +22,7 @@
 #include <asm/kvm_mmu.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/sysreg.h>
+#include <asm/virt.h>
 
 	.text
 	.pushsection	.hyp.idmap.text, "ax"
@@ -58,6 +59,9 @@ __invalid:
 	 * x2: HYP vectors
 	 */
 __do_hyp_init:
+	/* Check for a stub HVC call */
+	cmp	x0, #HVC_STUB_HCALL_NR
+	b.lo	__kvm_handle_stub_hvc
 
 	msr	ttbr0_el2, x0
 
@@ -119,6 +123,9 @@ __do_hyp_init:
 	eret
 ENDPROC(__kvm_hyp_init)
 
+ENTRY(__kvm_handle_stub_hvc)
+	cmp	x0, #HVC_RESET_VECTORS
+	b.ne	1f
 	/*
 	 * Reset kvm back to the hyp stub.
 	 */
@@ -133,9 +140,15 @@ ENTRY(__kvm_hyp_reset)
 	/* Install stub vectors */
 	adr_l	x0, __hyp_stub_vectors
 	msr	vbar_el2, x0
+	b	exit
 
+1:	/* Bad stub call */
+	ldr	x0, =HVC_STUB_ERR
+
+exit:
 	eret
 ENDPROC(__kvm_hyp_reset)
+ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
 
-- 
2.11.0

[PATCH v5 08/34] arm64: KVM: Implement HVC_GET_VECTORS in the init code

[Marc Zyngier]

Now that we have an infrastructure to handle hypercalls in the KVM
init code, let's implement HVC_GET_VECTORS there.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 5e39ad53bcae..fded932ede1b 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -124,7 +124,12 @@ __do_hyp_init:
 ENDPROC(__kvm_hyp_init)
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	x0, #HVC_RESET_VECTORS
+	cmp	x0, #HVC_GET_VECTORS
+	b.ne	1f
+	mrs	x0, vbar_el2
+	b	exit
+
+1:	cmp	x0, #HVC_RESET_VECTORS
 	b.ne	1f
 	/*
 	 * Reset kvm back to the hyp stub.
-- 
2.11.0

[PATCH v5 08/34] arm64: KVM: Implement HVC_GET_VECTORS in the init code

[Marc Zyngier]

Now that we have an infrastructure to handle hypercalls in the KVM
init code, let's implement HVC_GET_VECTORS there.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 5e39ad53bcae..fded932ede1b 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -124,7 +124,12 @@ __do_hyp_init:
 ENDPROC(__kvm_hyp_init)
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	x0, #HVC_RESET_VECTORS
+	cmp	x0, #HVC_GET_VECTORS
+	b.ne	1f
+	mrs	x0, vbar_el2
+	b	exit
+
+1:	cmp	x0, #HVC_RESET_VECTORS
 	b.ne	1f
 	/*
 	 * Reset kvm back to the hyp stub.
-- 
2.11.0

[PATCH v5 09/34] arm64: KVM: Allow the main HYP code to use the init hyp stub implementation

[Marc Zyngier]

We now have a full hyp-stub implementation in the KVM init code,
but the main KVM code only supports HVC_GET_VECTORS, which is not
enough.

Instead of reinventing the wheel, let's reuse the init implementation
by branching to the idmap page when called with a hyp-stub hypercall.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/hyp-entry.S | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index d8ef788646c6..4f34c5996f86 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -87,10 +87,24 @@ alternative_endif
 	/* Here, we're pretty sure the host called HVC. */
 	ldp	x0, x1, [sp], #16
 
-	cmp	x0, #HVC_GET_VECTORS
-	b.ne	1f
-	mrs	x0, vbar_el2
-	b	2f
+	/* Check for a stub HVC call */
+	cmp	x0, #HVC_STUB_HCALL_NR
+	b.hs	1f
+
+	/*
+	 * Compute the idmap address of __kvm_handle_stub_hvc and
+	 * jump there. Since we use kimage_voffset, do not use the
+	 * HYP VA for __kvm_handle_stub_hvc, but the kernel VA instead
+	 * (by loading it from the constant pool).
+	 *
+	 * Preserve x0-x4, which may contain stub parameters.
+	 */
+	ldr	x5, =__kvm_handle_stub_hvc
+	ldr_l	x6, kimage_voffset
+
+	/* x5 = __pa(x5) */
+	sub	x5, x5, x6
+	br	x5
 
 1:
 	/*
@@ -99,7 +113,7 @@ alternative_endif
 	kern_hyp_va	x0
 	do_el2_call
 
-2:	eret
+	eret
 
 el1_trap:
 	/*
-- 
2.11.0

[PATCH v5 09/34] arm64: KVM: Allow the main HYP code to use the init hyp stub implementation

[Marc Zyngier]

We now have a full hyp-stub implementation in the KVM init code,
but the main KVM code only supports HVC_GET_VECTORS, which is not
enough.

Instead of reinventing the wheel, let's reuse the init implementation
by branching to the idmap page when called with a hyp-stub hypercall.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp/hyp-entry.S | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index d8ef788646c6..4f34c5996f86 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -87,10 +87,24 @@ alternative_endif
 	/* Here, we're pretty sure the host called HVC. */
 	ldp	x0, x1, [sp], #16
 
-	cmp	x0, #HVC_GET_VECTORS
-	b.ne	1f
-	mrs	x0, vbar_el2
-	b	2f
+	/* Check for a stub HVC call */
+	cmp	x0, #HVC_STUB_HCALL_NR
+	b.hs	1f
+
+	/*
+	 * Compute the idmap address of __kvm_handle_stub_hvc and
+	 * jump there. Since we use kimage_voffset, do not use the
+	 * HYP VA for __kvm_handle_stub_hvc, but the kernel VA instead
+	 * (by loading it from the constant pool).
+	 *
+	 * Preserve x0-x4, which may contain stub parameters.
+	 */
+	ldr	x5, =__kvm_handle_stub_hvc
+	ldr_l	x6, kimage_voffset
+
+	/* x5 = __pa(x5) */
+	sub	x5, x5, x6
+	br	x5
 
 1:
 	/*
@@ -99,7 +113,7 @@ alternative_endif
 	kern_hyp_va	x0
 	do_el2_call
 
-2:	eret
+	eret
 
 el1_trap:
 	/*
-- 
2.11.0

[PATCH v5 10/34] arm64: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors

[Marc Zyngier]

We are now able to use the hyp stub to reset HYP mode. Time to
kiss __kvm_hyp_reset goodbye, and use __hyp_reset_vectors.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/kvm_asm.h  |  1 -
 arch/arm64/include/asm/kvm_host.h |  3 +--
 arch/arm64/kvm/hyp-init.S         |  2 --
 arch/arm64/kvm/hyp/hyp-entry.S    | 15 ---------------
 4 files changed, 1 insertion(+), 20 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 1769380a8fc0..60941c3c35f7 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -47,7 +47,6 @@ struct kvm_vcpu;
 
 extern char __kvm_hyp_init[];
 extern char __kvm_hyp_init_end[];
-extern char __kvm_hyp_reset[];
 
 extern char __kvm_hyp_vector[];
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e7705e7bb07b..0355dd109956 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -362,11 +362,10 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 	__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
 }
 
-void __kvm_hyp_teardown(void);
 static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
 					phys_addr_t phys_idmap_start)
 {
-	kvm_call_hyp(__kvm_hyp_teardown, phys_idmap_start);
+	__hyp_reset_vectors();
 }
 
 static inline void kvm_arch_hardware_unsetup(void) {}
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index fded932ede1b..b7a8f12293cc 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -134,7 +134,6 @@ ENTRY(__kvm_handle_stub_hvc)
 	/*
 	 * Reset kvm back to the hyp stub.
 	 */
-ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
 	mrs	x0, sctlr_el2
 	ldr	x1, =SCTLR_ELx_FLAGS
@@ -152,7 +151,6 @@ ENTRY(__kvm_hyp_reset)
 
 exit:
 	eret
-ENDPROC(__kvm_hyp_reset)
 ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 4f34c5996f86..5170ce1021da 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -53,21 +53,6 @@ ENTRY(__vhe_hyp_call)
 	ret
 ENDPROC(__vhe_hyp_call)
 
-/*
- * Compute the idmap address of __kvm_hyp_reset based on the idmap
- * start passed as a parameter, and jump there.
- *
- * x0: HYP phys_idmap_start
- */
-ENTRY(__kvm_hyp_teardown)
-	mov	x4, x0
-	adr_l	x3, __kvm_hyp_reset
-
-	/* insert __kvm_hyp_reset()s offset into phys_idmap_start */
-	bfi	x4, x3, #0, #PAGE_SHIFT
-	br	x4
-ENDPROC(__kvm_hyp_teardown)
-	
 el1_sync:				// Guest trapped into EL2
 	stp	x0, x1, [sp, #-16]!
 
-- 
2.11.0

[PATCH v5 10/34] arm64: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors

[Marc Zyngier]

We are now able to use the hyp stub to reset HYP mode. Time to
kiss __kvm_hyp_reset goodbye, and use __hyp_reset_vectors.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/kvm_asm.h  |  1 -
 arch/arm64/include/asm/kvm_host.h |  3 +--
 arch/arm64/kvm/hyp-init.S         |  2 --
 arch/arm64/kvm/hyp/hyp-entry.S    | 15 ---------------
 4 files changed, 1 insertion(+), 20 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 1769380a8fc0..60941c3c35f7 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -47,7 +47,6 @@ struct kvm_vcpu;
 
 extern char __kvm_hyp_init[];
 extern char __kvm_hyp_init_end[];
-extern char __kvm_hyp_reset[];
 
 extern char __kvm_hyp_vector[];
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e7705e7bb07b..0355dd109956 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -362,11 +362,10 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 	__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
 }
 
-void __kvm_hyp_teardown(void);
 static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
 					phys_addr_t phys_idmap_start)
 {
-	kvm_call_hyp(__kvm_hyp_teardown, phys_idmap_start);
+	__hyp_reset_vectors();
 }
 
 static inline void kvm_arch_hardware_unsetup(void) {}
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index fded932ede1b..b7a8f12293cc 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -134,7 +134,6 @@ ENTRY(__kvm_handle_stub_hvc)
 	/*
 	 * Reset kvm back to the hyp stub.
 	 */
-ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
 	mrs	x0, sctlr_el2
 	ldr	x1, =SCTLR_ELx_FLAGS
@@ -152,7 +151,6 @@ ENTRY(__kvm_hyp_reset)
 
 exit:
 	eret
-ENDPROC(__kvm_hyp_reset)
 ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 4f34c5996f86..5170ce1021da 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -53,21 +53,6 @@ ENTRY(__vhe_hyp_call)
 	ret
 ENDPROC(__vhe_hyp_call)
 
-/*
- * Compute the idmap address of __kvm_hyp_reset based on the idmap
- * start passed as a parameter, and jump there.
- *
- * x0: HYP phys_idmap_start
- */
-ENTRY(__kvm_hyp_teardown)
-	mov	x4, x0
-	adr_l	x3, __kvm_hyp_reset
-
-	/* insert __kvm_hyp_reset()s offset into phys_idmap_start */
-	bfi	x4, x3, #0, #PAGE_SHIFT
-	br	x4
-ENDPROC(__kvm_hyp_teardown)
-	
 el1_sync:				// Guest trapped into EL2
 	stp	x0, x1, [sp, #-16]!
 
-- 
2.11.0

[PATCH v5 11/34] arm64: KVM: Implement HVC_SOFT_RESTART in the init code

[Marc Zyngier]

Another missing stub hypercall is HVC_SOFT_RESTART. It turns out
that it is pretty easy to implement in terms of HVC_RESET_VECTORS
(since it needs to turn the MMU off).

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index b7a8f12293cc..0ad34fd6d2fc 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -129,21 +129,36 @@ ENTRY(__kvm_handle_stub_hvc)
 	mrs	x0, vbar_el2
 	b	exit
 
+1:	cmp	x0, #HVC_SOFT_RESTART
+	b.ne	1f
+
+	/* This is where we're about to jump, staying at EL2 */
+	msr	elr_el2, x1
+	mov	x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT | PSR_MODE_EL2h)
+	msr	spsr_el2, x0
+
+	/* Shuffle the arguments, and don't come back */
+	mov	x0, x2
+	mov	x1, x3
+	mov	x2, x4
+	b	reset
+
 1:	cmp	x0, #HVC_RESET_VECTORS
 	b.ne	1f
+reset:
 	/*
-	 * Reset kvm back to the hyp stub.
+	 * Reset kvm back to the hyp stub. Do not clobber x0-x4 in
+	 * case we coming via HVC_SOFT_RESTART.
 	 */
-	/* We're now in idmap, disable MMU */
-	mrs	x0, sctlr_el2
-	ldr	x1, =SCTLR_ELx_FLAGS
-	bic	x0, x0, x1		// Clear SCTL_M and etc
-	msr	sctlr_el2, x0
+	mrs	x5, sctlr_el2
+	ldr	x6, =SCTLR_ELx_FLAGS
+	bic	x5, x5, x6		// Clear SCTL_M and etc
+	msr	sctlr_el2, x5
 	isb
 
 	/* Install stub vectors */
-	adr_l	x0, __hyp_stub_vectors
-	msr	vbar_el2, x0
+	adr_l	x5, __hyp_stub_vectors
+	msr	vbar_el2, x5
 	b	exit
 
 1:	/* Bad stub call */
-- 
2.11.0

[PATCH v5 11/34] arm64: KVM: Implement HVC_SOFT_RESTART in the init code

[Marc Zyngier]

Another missing stub hypercall is HVC_SOFT_RESTART. It turns out
that it is pretty easy to implement in terms of HVC_RESET_VECTORS
(since it needs to turn the MMU off).

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index b7a8f12293cc..0ad34fd6d2fc 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -129,21 +129,36 @@ ENTRY(__kvm_handle_stub_hvc)
 	mrs	x0, vbar_el2
 	b	exit
 
+1:	cmp	x0, #HVC_SOFT_RESTART
+	b.ne	1f
+
+	/* This is where we're about to jump, staying at EL2 */
+	msr	elr_el2, x1
+	mov	x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT | PSR_MODE_EL2h)
+	msr	spsr_el2, x0
+
+	/* Shuffle the arguments, and don't come back */
+	mov	x0, x2
+	mov	x1, x3
+	mov	x2, x4
+	b	reset
+
 1:	cmp	x0, #HVC_RESET_VECTORS
 	b.ne	1f
+reset:
 	/*
-	 * Reset kvm back to the hyp stub.
+	 * Reset kvm back to the hyp stub. Do not clobber x0-x4 in
+	 * case we coming via HVC_SOFT_RESTART.
 	 */
-	/* We're now in idmap, disable MMU */
-	mrs	x0, sctlr_el2
-	ldr	x1, =SCTLR_ELx_FLAGS
-	bic	x0, x0, x1		// Clear SCTL_M and etc
-	msr	sctlr_el2, x0
+	mrs	x5, sctlr_el2
+	ldr	x6, =SCTLR_ELx_FLAGS
+	bic	x5, x5, x6		// Clear SCTL_M and etc
+	msr	sctlr_el2, x5
 	isb
 
 	/* Install stub vectors */
-	adr_l	x0, __hyp_stub_vectors
-	msr	vbar_el2, x0
+	adr_l	x5, __hyp_stub_vectors
+	msr	vbar_el2, x5
 	b	exit
 
 1:	/* Bad stub call */
-- 
2.11.0

[PATCH v5 12/34] ARM: hyp-stub: improve ABI

[Marc Zyngier]

From: Russell King <rmk+kernel@armlinux.org.uk>

Improve the hyp-stub ABI to allow it to do more than just get/set the
vectors.  We follow the example in ARM64, where r0 is used as an opcode
with the other registers as an argument.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kernel/hyp-stub.S | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15d073ae5da2..f3e9ba5fb642 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -22,6 +22,9 @@
 #include <asm/assembler.h>
 #include <asm/virt.h>
 
+#define HVC_GET_VECTORS 0
+#define HVC_SET_VECTORS 1
+
 #ifndef ZIMAGE
 /*
  * For the kernel proper, we need to find out the CPU boot mode long after
@@ -202,9 +205,19 @@ ARM_BE8(orr	r7, r7, #(1 << 25))     @ HSCTLR.EE
 ENDPROC(__hyp_stub_install_secondary)
 
 __hyp_stub_do_trap:
-	cmp	r0, #-1
-	mrceq	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	mcrne	p15, 4, r0, c12, c0, 0	@ set HVBAR
+	teq	r0, #HVC_GET_VECTORS
+	bne	1f
+	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
+	b	__hyp_stub_exit
+
+1:	teq	r0, #HVC_SET_VECTORS
+	bne	1f
+	mcr	p15, 4, r1, c12, c0, 0	@ set HVBAR
+	b	__hyp_stub_exit
+
+1:	mov	r0, #-1
+
+__hyp_stub_exit:
 	__ERET
 ENDPROC(__hyp_stub_do_trap)
 
@@ -231,10 +244,14 @@ ENDPROC(__hyp_stub_do_trap)
  * initialisation entry point.
  */
 ENTRY(__hyp_get_vectors)
-	mov	r0, #-1
+	mov	r0, #HVC_GET_VECTORS
+	__HVC(0)
+	ret	lr
 ENDPROC(__hyp_get_vectors)
-	@ fall through
+
 ENTRY(__hyp_set_vectors)
+	mov	r1, r0
+	mov	r0, #HVC_SET_VECTORS
 	__HVC(0)
 	ret	lr
 ENDPROC(__hyp_set_vectors)
-- 
2.11.0

[PATCH v5 12/34] ARM: hyp-stub: improve ABI

[Marc Zyngier]

From: Russell King <rmk+kernel@armlinux.org.uk>

Improve the hyp-stub ABI to allow it to do more than just get/set the
vectors.  We follow the example in ARM64, where r0 is used as an opcode
with the other registers as an argument.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kernel/hyp-stub.S | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15d073ae5da2..f3e9ba5fb642 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -22,6 +22,9 @@
 #include <asm/assembler.h>
 #include <asm/virt.h>
 
+#define HVC_GET_VECTORS 0
+#define HVC_SET_VECTORS 1
+
 #ifndef ZIMAGE
 /*
  * For the kernel proper, we need to find out the CPU boot mode long after
@@ -202,9 +205,19 @@ ARM_BE8(orr	r7, r7, #(1 << 25))     @ HSCTLR.EE
 ENDPROC(__hyp_stub_install_secondary)
 
 __hyp_stub_do_trap:
-	cmp	r0, #-1
-	mrceq	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	mcrne	p15, 4, r0, c12, c0, 0	@ set HVBAR
+	teq	r0, #HVC_GET_VECTORS
+	bne	1f
+	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
+	b	__hyp_stub_exit
+
+1:	teq	r0, #HVC_SET_VECTORS
+	bne	1f
+	mcr	p15, 4, r1, c12, c0, 0	@ set HVBAR
+	b	__hyp_stub_exit
+
+1:	mov	r0, #-1
+
+__hyp_stub_exit:
 	__ERET
 ENDPROC(__hyp_stub_do_trap)
 
@@ -231,10 +244,14 @@ ENDPROC(__hyp_stub_do_trap)
  * initialisation entry point.
  */
 ENTRY(__hyp_get_vectors)
-	mov	r0, #-1
+	mov	r0, #HVC_GET_VECTORS
+	__HVC(0)
+	ret	lr
 ENDPROC(__hyp_get_vectors)
-	@ fall through
+
 ENTRY(__hyp_set_vectors)
+	mov	r1, r0
+	mov	r0, #HVC_SET_VECTORS
 	__HVC(0)
 	ret	lr
 ENDPROC(__hyp_set_vectors)
-- 
2.11.0

[PATCH v5 13/34] ARM: soft-reboot into same mode that we entered the kernel

[Marc Zyngier]

From: Russell King <rmk+kernel@armlinux.org.uk>

When we soft-reboot (eg, kexec) from one kernel into the next, we need
to ensure that we enter the new kernel in the same processor mode as
when we were entered, so that (eg) the new kernel can install its own
hypervisor - the old kernel's hypervisor will have been overwritten.

In order to do this, we need to pass a flag to cpu_reset() so it knows
what to do, and we need to modify the kernel's own hypervisor stub to
allow it to handle a soft-reboot.

As we are always guaranteed to install our own hypervisor if we're
entered in HYP32 mode, and KVM will have moved itself out of the way
on kexec/normal reboot, we can assume that our hypervisor is in place
when we want to kexec, so changing our hypervisor API should not be a
problem.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/proc-fns.h |  4 ++--
 arch/arm/kernel/hyp-stub.S      | 13 +++++++++++++
 arch/arm/kernel/reboot.c        |  7 +++++--
 arch/arm/mm/proc-v7.S           | 12 ++++++++----
 4 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 8877ad5ffe10..f2e1af45bd6f 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -43,7 +43,7 @@ extern struct processor {
 	/*
 	 * Special stuff for a reset
 	 */
-	void (*reset)(unsigned long addr) __attribute__((noreturn));
+	void (*reset)(unsigned long addr, bool hvc) __attribute__((noreturn));
 	/*
 	 * Idle the processor
 	 */
@@ -88,7 +88,7 @@ extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte);
 #else
 extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext);
 #endif
-extern void cpu_reset(unsigned long addr) __attribute__((noreturn));
+extern void cpu_reset(unsigned long addr, bool hvc) __attribute__((noreturn));
 
 /* These three are private to arch/arm/kernel/suspend.c */
 extern void cpu_do_suspend(void *);
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index f3e9ba5fb642..82915231c6f8 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -24,6 +24,7 @@
 
 #define HVC_GET_VECTORS 0
 #define HVC_SET_VECTORS 1
+#define HVC_SOFT_RESTART 2
 
 #ifndef ZIMAGE
 /*
@@ -215,6 +216,10 @@ __hyp_stub_do_trap:
 	mcr	p15, 4, r1, c12, c0, 0	@ set HVBAR
 	b	__hyp_stub_exit
 
+1:	teq	r0, #HVC_SOFT_RESTART
+	bne	1f
+	bx	r3
+
 1:	mov	r0, #-1
 
 __hyp_stub_exit:
@@ -256,6 +261,14 @@ ENTRY(__hyp_set_vectors)
 	ret	lr
 ENDPROC(__hyp_set_vectors)
 
+ENTRY(__hyp_soft_restart)
+	mov	r3, r0
+	mov	r0, #HVC_SOFT_RESTART
+	__HVC(0)
+	mov	r0, r3
+	ret	lr
+ENDPROC(__hyp_soft_restart)
+
 #ifndef ZIMAGE
 .align 2
 .L__boot_cpu_mode_offset:
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3fa867a2aae6..3b2aa9a9fe26 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -12,10 +12,11 @@
 
 #include <asm/cacheflush.h>
 #include <asm/idmap.h>
+#include <asm/virt.h>
 
 #include "reboot.h"
 
-typedef void (*phys_reset_t)(unsigned long);
+typedef void (*phys_reset_t)(unsigned long, bool);
 
 /*
  * Function pointers to optional machine specific functions
@@ -51,7 +52,9 @@ static void __soft_restart(void *addr)
 
 	/* Switch to the identity mapping. */
 	phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset);
-	phys_reset((unsigned long)addr);
+
+	/* original stub should be restored by kvm */
+	phys_reset((unsigned long)addr, is_hyp_mode_available());
 
 	/* Should never get here. */
 	BUG();
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index d00d52c9de3e..1846ca4255d0 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -53,11 +53,15 @@ ENDPROC(cpu_v7_proc_fin)
 	.align	5
 	.pushsection	.idmap.text, "ax"
 ENTRY(cpu_v7_reset)
-	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
-	bic	r1, r1, #0x1			@ ...............m
- THUMB(	bic	r1, r1, #1 << 30 )		@ SCTLR.TE (Thumb exceptions)
-	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
+	mrc	p15, 0, r2, c1, c0, 0		@ ctrl register
+	bic	r2, r2, #0x1			@ ...............m
+ THUMB(	bic	r2, r2, #1 << 30 )		@ SCTLR.TE (Thumb exceptions)
+	mcr	p15, 0, r2, c1, c0, 0		@ disable MMU
 	isb
+#ifdef CONFIG_ARM_VIRT_EXT
+	teq	r1, #0
+	bne	__hyp_soft_restart
+#endif
 	bx	r0
 ENDPROC(cpu_v7_reset)
 	.popsection
-- 
2.11.0

[PATCH v5 13/34] ARM: soft-reboot into same mode that we entered the kernel

[Marc Zyngier]

From: Russell King <rmk+kernel@armlinux.org.uk>

When we soft-reboot (eg, kexec) from one kernel into the next, we need
to ensure that we enter the new kernel in the same processor mode as
when we were entered, so that (eg) the new kernel can install its own
hypervisor - the old kernel's hypervisor will have been overwritten.

In order to do this, we need to pass a flag to cpu_reset() so it knows
what to do, and we need to modify the kernel's own hypervisor stub to
allow it to handle a soft-reboot.

As we are always guaranteed to install our own hypervisor if we're
entered in HYP32 mode, and KVM will have moved itself out of the way
on kexec/normal reboot, we can assume that our hypervisor is in place
when we want to kexec, so changing our hypervisor API should not be a
problem.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/proc-fns.h |  4 ++--
 arch/arm/kernel/hyp-stub.S      | 13 +++++++++++++
 arch/arm/kernel/reboot.c        |  7 +++++--
 arch/arm/mm/proc-v7.S           | 12 ++++++++----
 4 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 8877ad5ffe10..f2e1af45bd6f 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -43,7 +43,7 @@ extern struct processor {
 	/*
 	 * Special stuff for a reset
 	 */
-	void (*reset)(unsigned long addr) __attribute__((noreturn));
+	void (*reset)(unsigned long addr, bool hvc) __attribute__((noreturn));
 	/*
 	 * Idle the processor
 	 */
@@ -88,7 +88,7 @@ extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte);
 #else
 extern void cpu_set_pte_ext(pte_t *ptep, pte_t pte, unsigned int ext);
 #endif
-extern void cpu_reset(unsigned long addr) __attribute__((noreturn));
+extern void cpu_reset(unsigned long addr, bool hvc) __attribute__((noreturn));
 
 /* These three are private to arch/arm/kernel/suspend.c */
 extern void cpu_do_suspend(void *);
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index f3e9ba5fb642..82915231c6f8 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -24,6 +24,7 @@
 
 #define HVC_GET_VECTORS 0
 #define HVC_SET_VECTORS 1
+#define HVC_SOFT_RESTART 2
 
 #ifndef ZIMAGE
 /*
@@ -215,6 +216,10 @@ __hyp_stub_do_trap:
 	mcr	p15, 4, r1, c12, c0, 0	@ set HVBAR
 	b	__hyp_stub_exit
 
+1:	teq	r0, #HVC_SOFT_RESTART
+	bne	1f
+	bx	r3
+
 1:	mov	r0, #-1
 
 __hyp_stub_exit:
@@ -256,6 +261,14 @@ ENTRY(__hyp_set_vectors)
 	ret	lr
 ENDPROC(__hyp_set_vectors)
 
+ENTRY(__hyp_soft_restart)
+	mov	r3, r0
+	mov	r0, #HVC_SOFT_RESTART
+	__HVC(0)
+	mov	r0, r3
+	ret	lr
+ENDPROC(__hyp_soft_restart)
+
 #ifndef ZIMAGE
 .align 2
 .L__boot_cpu_mode_offset:
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3fa867a2aae6..3b2aa9a9fe26 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -12,10 +12,11 @@
 
 #include <asm/cacheflush.h>
 #include <asm/idmap.h>
+#include <asm/virt.h>
 
 #include "reboot.h"
 
-typedef void (*phys_reset_t)(unsigned long);
+typedef void (*phys_reset_t)(unsigned long, bool);
 
 /*
  * Function pointers to optional machine specific functions
@@ -51,7 +52,9 @@ static void __soft_restart(void *addr)
 
 	/* Switch to the identity mapping. */
 	phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset);
-	phys_reset((unsigned long)addr);
+
+	/* original stub should be restored by kvm */
+	phys_reset((unsigned long)addr, is_hyp_mode_available());
 
 	/* Should never get here. */
 	BUG();
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index d00d52c9de3e..1846ca4255d0 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -53,11 +53,15 @@ ENDPROC(cpu_v7_proc_fin)
 	.align	5
 	.pushsection	.idmap.text, "ax"
 ENTRY(cpu_v7_reset)
-	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
-	bic	r1, r1, #0x1			@ ...............m
- THUMB(	bic	r1, r1, #1 << 30 )		@ SCTLR.TE (Thumb exceptions)
-	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
+	mrc	p15, 0, r2, c1, c0, 0		@ ctrl register
+	bic	r2, r2, #0x1			@ ...............m
+ THUMB(	bic	r2, r2, #1 << 30 )		@ SCTLR.TE (Thumb exceptions)
+	mcr	p15, 0, r2, c1, c0, 0		@ disable MMU
 	isb
+#ifdef CONFIG_ARM_VIRT_EXT
+	teq	r1, #0
+	bne	__hyp_soft_restart
+#endif
 	bx	r0
 ENDPROC(cpu_v7_reset)
 	.popsection
-- 
2.11.0

[PATCH v5 14/34] ARM: KVM: Convert KVM to use HVC_GET_VECTORS

[Marc Zyngier]

The conversion of the HYP stub ABI to something similar to arm64
left the KVM code broken, as it doesn't know about the new
stub numbering. Let's move the various #defines to virt.h, and
let KVM use HVC_GET_VECTORS.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h  | 8 ++++++++
 arch/arm/kernel/hyp-stub.S   | 4 ----
 arch/arm/kvm/hyp/hyp-entry.S | 2 +-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 6dae1956c74d..4ea16fcaf2ed 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -94,6 +94,14 @@ extern char __hyp_text_start[];
 extern char __hyp_text_end[];
 #endif
 
+#else
+
+/* Only assembly code should need those */
+
+#define HVC_GET_VECTORS 0
+#define HVC_SET_VECTORS 1
+#define HVC_SOFT_RESTART 2
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* ! VIRT_H */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 82915231c6f8..8301db963d83 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -22,10 +22,6 @@
 #include <asm/assembler.h>
 #include <asm/virt.h>
 
-#define HVC_GET_VECTORS 0
-#define HVC_SET_VECTORS 1
-#define HVC_SOFT_RESTART 2
-
 #ifndef ZIMAGE
 /*
  * For the kernel proper, we need to find out the CPU boot mode long after
diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 96beb53934c9..1f8db7d21fc5 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -127,7 +127,7 @@ hyp_hvc:
 	pop	{r0, r1, r2}
 
 	/* Check for __hyp_get_vectors */
-	cmp	r0, #-1
+	cmp	r0, #HVC_GET_VECTORS
 	mrceq	p15, 4, r0, c12, c0, 0	@ get HVBAR
 	beq	1f
 
-- 
2.11.0

[PATCH v5 14/34] ARM: KVM: Convert KVM to use HVC_GET_VECTORS

[Marc Zyngier]

The conversion of the HYP stub ABI to something similar to arm64
left the KVM code broken, as it doesn't know about the new
stub numbering. Let's move the various #defines to virt.h, and
let KVM use HVC_GET_VECTORS.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h  | 8 ++++++++
 arch/arm/kernel/hyp-stub.S   | 4 ----
 arch/arm/kvm/hyp/hyp-entry.S | 2 +-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 6dae1956c74d..4ea16fcaf2ed 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -94,6 +94,14 @@ extern char __hyp_text_start[];
 extern char __hyp_text_end[];
 #endif
 
+#else
+
+/* Only assembly code should need those */
+
+#define HVC_GET_VECTORS 0
+#define HVC_SET_VECTORS 1
+#define HVC_SOFT_RESTART 2
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* ! VIRT_H */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 82915231c6f8..8301db963d83 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -22,10 +22,6 @@
 #include <asm/assembler.h>
 #include <asm/virt.h>
 
-#define HVC_GET_VECTORS 0
-#define HVC_SET_VECTORS 1
-#define HVC_SOFT_RESTART 2
-
 #ifndef ZIMAGE
 /*
  * For the kernel proper, we need to find out the CPU boot mode long after
diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 96beb53934c9..1f8db7d21fc5 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -127,7 +127,7 @@ hyp_hvc:
 	pop	{r0, r1, r2}
 
 	/* Check for __hyp_get_vectors */
-	cmp	r0, #-1
+	cmp	r0, #HVC_GET_VECTORS
 	mrceq	p15, 4, r0, c12, c0, 0	@ get HVBAR
 	beq	1f
 
-- 
2.11.0

[PATCH v5 15/34] ARM: Update cpu_v7_reset documentation

[Marc Zyngier]

cpu_v7_reset() now takes a second parameter indicating whether
we should reboot in HYP or not. Update the documentation to
reflect this.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mm/proc-v7.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 1846ca4255d0..01d64c0b2563 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -39,13 +39,14 @@ ENTRY(cpu_v7_proc_fin)
 ENDPROC(cpu_v7_proc_fin)
 
 /*
- *	cpu_v7_reset(loc)
+ *	cpu_v7_reset(loc, hyp)
  *
  *	Perform a soft reset of the system.  Put the CPU into the
  *	same state as it would be if it had been reset, and branch
  *	to what would be the reset vector.
  *
  *	- loc   - location to jump to for soft reset
+ *	- hyp   - indicate if restart occurs in HYP mode
  *
  *	This code must be executed using a flat identity mapping with
  *      caches disabled.
-- 
2.11.0

[PATCH v5 15/34] ARM: Update cpu_v7_reset documentation

[Marc Zyngier]

cpu_v7_reset() now takes a second parameter indicating whether
we should reboot in HYP or not. Update the documentation to
reflect this.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mm/proc-v7.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 1846ca4255d0..01d64c0b2563 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -39,13 +39,14 @@ ENTRY(cpu_v7_proc_fin)
 ENDPROC(cpu_v7_proc_fin)
 
 /*
- *	cpu_v7_reset(loc)
+ *	cpu_v7_reset(loc, hyp)
  *
  *	Perform a soft reset of the system.  Put the CPU into the
  *	same state as it would be if it had been reset, and branch
  *	to what would be the reset vector.
  *
  *	- loc   - location to jump to for soft reset
+ *	- hyp   - indicate if restart occurs in HYP mode
  *
  *	This code must be executed using a flat identity mapping with
  *      caches disabled.
-- 
2.11.0

[PATCH v5 16/34] ARM: hyp-stub: Use r1 for the soft-restart address

[Marc Zyngier]

It is not really obvious why the restart address should be in r3
when communicated to the hyp-stub. r1 should be perfectly adequate,
and consistent with the rest of the code.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kernel/hyp-stub.S | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 8301db963d83..15eaa14322a7 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -214,7 +214,7 @@ __hyp_stub_do_trap:
 
 1:	teq	r0, #HVC_SOFT_RESTART
 	bne	1f
-	bx	r3
+	bx	r1
 
 1:	mov	r0, #-1
 
@@ -258,10 +258,9 @@ ENTRY(__hyp_set_vectors)
 ENDPROC(__hyp_set_vectors)
 
 ENTRY(__hyp_soft_restart)
-	mov	r3, r0
+	mov	r1, r0
 	mov	r0, #HVC_SOFT_RESTART
 	__HVC(0)
-	mov	r0, r3
 	ret	lr
 ENDPROC(__hyp_soft_restart)
 
-- 
2.11.0

[PATCH v5 16/34] ARM: hyp-stub: Use r1 for the soft-restart address

[Marc Zyngier]

It is not really obvious why the restart address should be in r3
when communicated to the hyp-stub. r1 should be perfectly adequate,
and consistent with the rest of the code.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kernel/hyp-stub.S | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 8301db963d83..15eaa14322a7 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -214,7 +214,7 @@ __hyp_stub_do_trap:
 
 1:	teq	r0, #HVC_SOFT_RESTART
 	bne	1f
-	bx	r3
+	bx	r1
 
 1:	mov	r0, #-1
 
@@ -258,10 +258,9 @@ ENTRY(__hyp_set_vectors)
 ENDPROC(__hyp_set_vectors)
 
 ENTRY(__hyp_soft_restart)
-	mov	r3, r0
+	mov	r1, r0
 	mov	r0, #HVC_SOFT_RESTART
 	__HVC(0)
-	mov	r0, r3
 	ret	lr
 ENDPROC(__hyp_soft_restart)
 
-- 
2.11.0

[PATCH v5 17/34] ARM: Expose the VA/IDMAP offset

[Marc Zyngier]

The KVM code needs to be able to compute the address of
symbols in its idmap page (the equivalent of a virt_to_idmap()
call). Unfortunately, virt_to_idmap is slightly complicated,
depending on the use of arch_phys_to_idmap_offset or not, and
none of that is readily available at HYP.

Instead, expose a single kimage_voffset variable which contains the
offset between a kernel VA and its idmap address, enabling the
VA->IDMAP conversion. This allows the KVM code to behave similarily
to its arm64 counterpart.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mm/mmu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4e016d7f37b3..e98a2b5c4e85 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -87,6 +87,8 @@ struct cachepolicy {
 #define s2_policy(policy)	0
 #endif
 
+unsigned long kimage_voffset __ro_after_init;
+
 static struct cachepolicy cache_policies[] __initdata = {
 	{
 		.policy		= "uncached",
@@ -1635,4 +1637,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 
 	empty_zero_page = virt_to_page(zero_page);
 	__flush_dcache_page(NULL, empty_zero_page);
+
+	/* Compute the virt/idmap offset, mostly for the sake of KVM */
+	kimage_voffset = (unsigned long)&kimage_voffset - virt_to_idmap(&kimage_voffset);
 }
-- 
2.11.0

[PATCH v5 17/34] ARM: Expose the VA/IDMAP offset

[Marc Zyngier]

The KVM code needs to be able to compute the address of
symbols in its idmap page (the equivalent of a virt_to_idmap()
call). Unfortunately, virt_to_idmap is slightly complicated,
depending on the use of arch_phys_to_idmap_offset or not, and
none of that is readily available at HYP.

Instead, expose a single kimage_voffset variable which contains the
offset between a kernel VA and its idmap address, enabling the
VA->IDMAP conversion. This allows the KVM code to behave similarily
to its arm64 counterpart.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/mm/mmu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4e016d7f37b3..e98a2b5c4e85 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -87,6 +87,8 @@ struct cachepolicy {
 #define s2_policy(policy)	0
 #endif
 
+unsigned long kimage_voffset __ro_after_init;
+
 static struct cachepolicy cache_policies[] __initdata = {
 	{
 		.policy		= "uncached",
@@ -1635,4 +1637,7 @@ void __init paging_init(const struct machine_desc *mdesc)
 
 	empty_zero_page = virt_to_page(zero_page);
 	__flush_dcache_page(NULL, empty_zero_page);
+
+	/* Compute the virt/idmap offset, mostly for the sake of KVM */
+	kimage_voffset = (unsigned long)&kimage_voffset - virt_to_idmap(&kimage_voffset);
 }
-- 
2.11.0

[PATCH v5 18/34] ARM: hyp-stub: Define a return value for failed stub calls

[Marc Zyngier]

Define a standard return value to be returned when a hyp stub
call fails.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h | 2 ++
 arch/arm/kernel/hyp-stub.S  | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 4ea16fcaf2ed..c16f70d6953f 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -104,4 +104,6 @@ extern char __hyp_text_end[];
 
 #endif /* __ASSEMBLY__ */
 
+#define HVC_STUB_ERR	0xbadca11
+
 #endif /* ! VIRT_H */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15eaa14322a7..b20ca8815911 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -216,7 +216,7 @@ __hyp_stub_do_trap:
 	bne	1f
 	bx	r1
 
-1:	mov	r0, #-1
+1:	ldr	r0, =HVC_STUB_ERR
 
 __hyp_stub_exit:
 	__ERET
-- 
2.11.0

[PATCH v5 18/34] ARM: hyp-stub: Define a return value for failed stub calls

[Marc Zyngier]

Define a standard return value to be returned when a hyp stub
call fails.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h | 2 ++
 arch/arm/kernel/hyp-stub.S  | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 4ea16fcaf2ed..c16f70d6953f 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -104,4 +104,6 @@ extern char __hyp_text_end[];
 
 #endif /* __ASSEMBLY__ */
 
+#define HVC_STUB_ERR	0xbadca11
+
 #endif /* ! VIRT_H */
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 15eaa14322a7..b20ca8815911 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -216,7 +216,7 @@ __hyp_stub_do_trap:
 	bne	1f
 	bx	r1
 
-1:	mov	r0, #-1
+1:	ldr	r0, =HVC_STUB_ERR
 
 __hyp_stub_exit:
 	__ERET
-- 
2.11.0

[PATCH v5 19/34] ARM: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

Let's define a new stub hypercall that resets the HYP configuration
to its default: hyp-stub vectors, and MMU disabled.

Of course, for the hyp-stub itself, this is a trivial no-op.
Hypervisors will have a bit more work to do.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h |  3 +++
 arch/arm/kernel/hyp-stub.S  | 11 ++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index c16f70d6953f..c5a27570b225 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -101,6 +101,9 @@ extern char __hyp_text_end[];
 #define HVC_GET_VECTORS 0
 #define HVC_SET_VECTORS 1
 #define HVC_SOFT_RESTART 2
+#define HVC_RESET_VECTORS 3
+
+#define HVC_STUB_HCALL_NR 4
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index b20ca8815911..e637854335aa 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -216,7 +216,10 @@ __hyp_stub_do_trap:
 	bne	1f
 	bx	r1
 
-1:	ldr	r0, =HVC_STUB_ERR
+1:	teq	r0, #HVC_RESET_VECTORS
+	beq	__hyp_stub_exit
+
+	ldr	r0, =HVC_STUB_ERR
 
 __hyp_stub_exit:
 	__ERET
@@ -264,6 +267,12 @@ ENTRY(__hyp_soft_restart)
 	ret	lr
 ENDPROC(__hyp_soft_restart)
 
+ENTRY(__hyp_reset_vectors)
+	mov	r0, #HVC_RESET_VECTORS
+	__HVC(0)
+	ret	lr
+ENDPROC(__hyp_reset_vectors)
+
 #ifndef ZIMAGE
 .align 2
 .L__boot_cpu_mode_offset:
-- 
2.11.0

[PATCH v5 19/34] ARM: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

Let's define a new stub hypercall that resets the HYP configuration
to its default: hyp-stub vectors, and MMU disabled.

Of course, for the hyp-stub itself, this is a trivial no-op.
Hypervisors will have a bit more work to do.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h |  3 +++
 arch/arm/kernel/hyp-stub.S  | 11 ++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index c16f70d6953f..c5a27570b225 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -101,6 +101,9 @@ extern char __hyp_text_end[];
 #define HVC_GET_VECTORS 0
 #define HVC_SET_VECTORS 1
 #define HVC_SOFT_RESTART 2
+#define HVC_RESET_VECTORS 3
+
+#define HVC_STUB_HCALL_NR 4
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index b20ca8815911..e637854335aa 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -216,7 +216,10 @@ __hyp_stub_do_trap:
 	bne	1f
 	bx	r1
 
-1:	ldr	r0, =HVC_STUB_ERR
+1:	teq	r0, #HVC_RESET_VECTORS
+	beq	__hyp_stub_exit
+
+	ldr	r0, =HVC_STUB_ERR
 
 __hyp_stub_exit:
 	__ERET
@@ -264,6 +267,12 @@ ENTRY(__hyp_soft_restart)
 	ret	lr
 ENDPROC(__hyp_soft_restart)
 
+ENTRY(__hyp_reset_vectors)
+	mov	r0, #HVC_RESET_VECTORS
+	__HVC(0)
+	ret	lr
+ENDPROC(__hyp_reset_vectors)
+
 #ifndef ZIMAGE
 .align 2
 .L__boot_cpu_mode_offset:
-- 
2.11.0

[PATCH v5 20/34] ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code

[Marc Zyngier]

In order to restore HYP mode to its original condition, KVM currently
implements __kvm_hyp_reset(). As we're moving towards a hyp-stub
defined API, it becomes necessary to implement HVC_RESET_VECTORS.

This patch adds the HVC_RESET_VECTORS hypercall to the KVM init
code, which so far lacked any form of hypercall support.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h |  1 +
 arch/arm/kernel/hyp-stub.S  |  2 +-
 arch/arm/kvm/init.S         | 33 +++++++++++++++++++++++++++------
 3 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index c5a27570b225..663adc09c918 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -54,6 +54,7 @@ static inline void sync_boot_mode(void)
 
 void __hyp_set_vectors(unsigned long phys_vector_base);
 unsigned long __hyp_get_vectors(void);
+void __hyp_reset_vectors(void);
 #else
 #define __boot_cpu_mode	(SVC_MODE)
 #define sync_boot_mode()
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index e637854335aa..675c50f5cb5c 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -280,7 +280,7 @@ ENDPROC(__hyp_reset_vectors)
 #endif
 
 .align 5
-__hyp_stub_vectors:
+ENTRY(__hyp_stub_vectors)
 __hyp_stub_reset:	W(b)	.
 __hyp_stub_und:		W(b)	.
 __hyp_stub_svc:		W(b)	.
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index bf89c919efc1..86a7008e75a3 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -23,6 +23,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_mmu.h>
+#include <asm/virt.h>
 
 /********************************************************************
  * Hypervisor initialization
@@ -39,6 +40,10 @@
  * - Setup the page tables
  * - Enable the MMU
  * - Profit! (or eret, if you only care about the code).
+ *
+ * Another possibility is to get a HYP stub hypercall.
+ * We discriminate between the two by checking if r0 contains a value
+ * that is less than HVC_STUB_HCALL_NR.
  */
 
 	.text
@@ -58,6 +63,10 @@ __kvm_hyp_init:
 	W(b)	.
 
 __do_hyp_init:
+	@ Check for a stub hypercall
+	cmp	r0, #HVC_STUB_HCALL_NR
+	blo	__kvm_handle_stub_hvc
+
 	@ Set stack pointer
 	mov	sp, r0
 
@@ -112,19 +121,31 @@ __do_hyp_init:
 
 	eret
 
-	@ r0 : stub vectors address
+ENTRY(__kvm_handle_stub_hvc)
+	cmp	r0, #HVC_RESET_VECTORS
+	bne	1f
 ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
 	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
-	ldr	r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
-	bic	r1, r1, r2
+	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
+	bic	r1, r1, r0
 	mcr	p15, 4, r1, c1, c0, 0	@ HSCTLR
 
-	/* Install stub vectors */
-	mcr	p15, 4, r0, c12, c0, 0	@ HVBAR
-	isb
+	/*
+	 * Install stub vectors, using ardb's VA->PA trick.
+	 */
+0:	adr	r0, 0b					@ PA(0)
+	movw	r1, #:lower16:__hyp_stub_vectors - 0b   @ VA(stub) - VA(0)
+	movt	r1, #:upper16:__hyp_stub_vectors - 0b
+	add	r1, r1, r0				@ PA(stub)
+	mcr	p15, 4, r1, c12, c0, 0	@ HVBAR
+	b	exit
+
+1:	ldr	r0, =HVC_STUB_ERR
 
+exit:
 	eret
+ENDPROC(__kvm_handle_stub_hvc)
 ENDPROC(__kvm_hyp_reset)
 
 	.ltorg
-- 
2.11.0

[PATCH v5 20/34] ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code

[Marc Zyngier]

In order to restore HYP mode to its original condition, KVM currently
implements __kvm_hyp_reset(). As we're moving towards a hyp-stub
defined API, it becomes necessary to implement HVC_RESET_VECTORS.

This patch adds the HVC_RESET_VECTORS hypercall to the KVM init
code, which so far lacked any form of hypercall support.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h |  1 +
 arch/arm/kernel/hyp-stub.S  |  2 +-
 arch/arm/kvm/init.S         | 33 +++++++++++++++++++++++++++------
 3 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index c5a27570b225..663adc09c918 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -54,6 +54,7 @@ static inline void sync_boot_mode(void)
 
 void __hyp_set_vectors(unsigned long phys_vector_base);
 unsigned long __hyp_get_vectors(void);
+void __hyp_reset_vectors(void);
 #else
 #define __boot_cpu_mode	(SVC_MODE)
 #define sync_boot_mode()
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index e637854335aa..675c50f5cb5c 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -280,7 +280,7 @@ ENDPROC(__hyp_reset_vectors)
 #endif
 
 .align 5
-__hyp_stub_vectors:
+ENTRY(__hyp_stub_vectors)
 __hyp_stub_reset:	W(b)	.
 __hyp_stub_und:		W(b)	.
 __hyp_stub_svc:		W(b)	.
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index bf89c919efc1..86a7008e75a3 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -23,6 +23,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_arm.h>
 #include <asm/kvm_mmu.h>
+#include <asm/virt.h>
 
 /********************************************************************
  * Hypervisor initialization
@@ -39,6 +40,10 @@
  * - Setup the page tables
  * - Enable the MMU
  * - Profit! (or eret, if you only care about the code).
+ *
+ * Another possibility is to get a HYP stub hypercall.
+ * We discriminate between the two by checking if r0 contains a value
+ * that is less than HVC_STUB_HCALL_NR.
  */
 
 	.text
@@ -58,6 +63,10 @@ __kvm_hyp_init:
 	W(b)	.
 
 __do_hyp_init:
+	@ Check for a stub hypercall
+	cmp	r0, #HVC_STUB_HCALL_NR
+	blo	__kvm_handle_stub_hvc
+
 	@ Set stack pointer
 	mov	sp, r0
 
@@ -112,19 +121,31 @@ __do_hyp_init:
 
 	eret
 
-	@ r0 : stub vectors address
+ENTRY(__kvm_handle_stub_hvc)
+	cmp	r0, #HVC_RESET_VECTORS
+	bne	1f
 ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
 	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
-	ldr	r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
-	bic	r1, r1, r2
+	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
+	bic	r1, r1, r0
 	mcr	p15, 4, r1, c1, c0, 0	@ HSCTLR
 
-	/* Install stub vectors */
-	mcr	p15, 4, r0, c12, c0, 0	@ HVBAR
-	isb
+	/*
+	 * Install stub vectors, using ardb's VA->PA trick.
+	 */
+0:	adr	r0, 0b					@ PA(0)
+	movw	r1, #:lower16:__hyp_stub_vectors - 0b   @ VA(stub) - VA(0)
+	movt	r1, #:upper16:__hyp_stub_vectors - 0b
+	add	r1, r1, r0				@ PA(stub)
+	mcr	p15, 4, r1, c12, c0, 0	@ HVBAR
+	b	exit
+
+1:	ldr	r0, =HVC_STUB_ERR
 
+exit:
 	eret
+ENDPROC(__kvm_handle_stub_hvc)
 ENDPROC(__kvm_hyp_reset)
 
 	.ltorg
-- 
2.11.0

[PATCH v5 21/34] ARM: KVM: Implement HVC_GET_VECTORS in the init code

[Marc Zyngier]

Now that we have an infrastructure to handle hypercalls in the KVM
init code, let's implement HVC_GET_VECTORS there.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/init.S | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 86a7008e75a3..d6b2f496fa13 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -122,7 +122,12 @@ __do_hyp_init:
 	eret
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	r0, #HVC_RESET_VECTORS
+	cmp	r0, #HVC_GET_VECTORS
+	bne	1f
+	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
+	b	exit
+
+1:	cmp	r0, #HVC_RESET_VECTORS
 	bne	1f
 ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
-- 
2.11.0

[PATCH v5 21/34] ARM: KVM: Implement HVC_GET_VECTORS in the init code

[Marc Zyngier]

Now that we have an infrastructure to handle hypercalls in the KVM
init code, let's implement HVC_GET_VECTORS there.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/init.S | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 86a7008e75a3..d6b2f496fa13 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -122,7 +122,12 @@ __do_hyp_init:
 	eret
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	r0, #HVC_RESET_VECTORS
+	cmp	r0, #HVC_GET_VECTORS
+	bne	1f
+	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
+	b	exit
+
+1:	cmp	r0, #HVC_RESET_VECTORS
 	bne	1f
 ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
-- 
2.11.0

[PATCH v5 22/34] ARM: KVM: Allow the main HYP code to use the init hyp stub implementation

[Marc Zyngier]

We now have a full hyp-stub implementation in the KVM init code,
but the main KVM code only supports HVC_GET_VECTORS, which is not
enough.

Instead of reinventing the wheel, let's reuse the init implementation
by branching to the idmap page when called with a hyp-stub hypercall.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/hyp/hyp-entry.S | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 1f8db7d21fc5..a35baa81fd23 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -126,11 +126,30 @@ hyp_hvc:
 	 */
 	pop	{r0, r1, r2}
 
-	/* Check for __hyp_get_vectors */
-	cmp	r0, #HVC_GET_VECTORS
-	mrceq	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	beq	1f
+	/*
+	 * Check if we have a kernel function, which is guaranteed to be
+	 * bigger than the maximum hyp stub hypercall
+	 */
+	cmp	r0, #HVC_STUB_HCALL_NR
+	bhs	1f
 
+	/*
+	 * Not a kernel function, treat it as a stub hypercall.
+	 * Compute the physical address for __kvm_handle_stub_hvc
+	 * (as the code lives in the idmaped page) and branch there.
+	 * We hijack ip (r12) as a tmp register.
+	 */
+	push	{r1}
+	ldr	r1, =kimage_voffset
+	ldr	r1, [r1]
+	ldr	ip, =__kvm_handle_stub_hvc
+	sub	ip, ip, r1
+THUMB(	add	ip, ip, #1)
+	pop	{r1}
+
+	bx	ip
+
+1:
 	push	{lr}
 
 	mov	lr, r0
@@ -142,7 +161,7 @@ THUMB(	orr	lr, #1)
 	blx	lr			@ Call the HYP function
 
 	pop	{lr}
-1:	eret
+	eret
 
 guest_trap:
 	load_vcpu r0			@ Load VCPU pointer to r0
-- 
2.11.0

[PATCH v5 22/34] ARM: KVM: Allow the main HYP code to use the init hyp stub implementation

[Marc Zyngier]

We now have a full hyp-stub implementation in the KVM init code,
but the main KVM code only supports HVC_GET_VECTORS, which is not
enough.

Instead of reinventing the wheel, let's reuse the init implementation
by branching to the idmap page when called with a hyp-stub hypercall.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/hyp/hyp-entry.S | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 1f8db7d21fc5..a35baa81fd23 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S
@@ -126,11 +126,30 @@ hyp_hvc:
 	 */
 	pop	{r0, r1, r2}
 
-	/* Check for __hyp_get_vectors */
-	cmp	r0, #HVC_GET_VECTORS
-	mrceq	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	beq	1f
+	/*
+	 * Check if we have a kernel function, which is guaranteed to be
+	 * bigger than the maximum hyp stub hypercall
+	 */
+	cmp	r0, #HVC_STUB_HCALL_NR
+	bhs	1f
 
+	/*
+	 * Not a kernel function, treat it as a stub hypercall.
+	 * Compute the physical address for __kvm_handle_stub_hvc
+	 * (as the code lives in the idmaped page) and branch there.
+	 * We hijack ip (r12) as a tmp register.
+	 */
+	push	{r1}
+	ldr	r1, =kimage_voffset
+	ldr	r1, [r1]
+	ldr	ip, =__kvm_handle_stub_hvc
+	sub	ip, ip, r1
+THUMB(	add	ip, ip, #1)
+	pop	{r1}
+
+	bx	ip
+
+1:
 	push	{lr}
 
 	mov	lr, r0
@@ -142,7 +161,7 @@ THUMB(	orr	lr, #1)
 	blx	lr			@ Call the HYP function
 
 	pop	{lr}
-1:	eret
+	eret
 
 guest_trap:
 	load_vcpu r0			@ Load VCPU pointer to r0
-- 
2.11.0

[PATCH v5 23/34] ARM: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors

[Marc Zyngier]

We are now able to use the hyp stub to reset HYP mode. Time to
kiss __kvm_hyp_reset goodbye, and use __hyp_reset_vectors.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_asm.h  | 2 --
 arch/arm/include/asm/kvm_host.h | 2 +-
 arch/arm/kvm/init.S             | 2 --
 3 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 8ef05381984b..7ccb6f1aac5b 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -72,8 +72,6 @@ extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 
 extern void __init_stage2_translation(void);
 
-extern void __kvm_hyp_reset(unsigned long);
-
 extern u64 __vgic_v3_get_ich_vtr_el2(void);
 extern void __vgic_v3_init_lrs(void);
 #endif
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 31ee468ce667..adea30753185 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -273,7 +273,7 @@ static inline void __cpu_init_stage2(void)
 static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
 					phys_addr_t phys_idmap_start)
 {
-	kvm_call_hyp((void *)virt_to_idmap(__kvm_hyp_reset), vector_ptr);
+	__hyp_reset_vectors();
 }
 
 static inline int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index d6b2f496fa13..fb336090ee9c 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -129,7 +129,6 @@ ENTRY(__kvm_handle_stub_hvc)
 
 1:	cmp	r0, #HVC_RESET_VECTORS
 	bne	1f
-ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
 	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
 	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
@@ -151,7 +150,6 @@ ENTRY(__kvm_hyp_reset)
 exit:
 	eret
 ENDPROC(__kvm_handle_stub_hvc)
-ENDPROC(__kvm_hyp_reset)
 
 	.ltorg
 
-- 
2.11.0

[PATCH v5 23/34] ARM: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors

[Marc Zyngier]

We are now able to use the hyp stub to reset HYP mode. Time to
kiss __kvm_hyp_reset goodbye, and use __hyp_reset_vectors.

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_asm.h  | 2 --
 arch/arm/include/asm/kvm_host.h | 2 +-
 arch/arm/kvm/init.S             | 2 --
 3 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 8ef05381984b..7ccb6f1aac5b 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -72,8 +72,6 @@ extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
 
 extern void __init_stage2_translation(void);
 
-extern void __kvm_hyp_reset(unsigned long);
-
 extern u64 __vgic_v3_get_ich_vtr_el2(void);
 extern void __vgic_v3_init_lrs(void);
 #endif
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 31ee468ce667..adea30753185 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -273,7 +273,7 @@ static inline void __cpu_init_stage2(void)
 static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
 					phys_addr_t phys_idmap_start)
 {
-	kvm_call_hyp((void *)virt_to_idmap(__kvm_hyp_reset), vector_ptr);
+	__hyp_reset_vectors();
 }
 
 static inline int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index d6b2f496fa13..fb336090ee9c 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -129,7 +129,6 @@ ENTRY(__kvm_handle_stub_hvc)
 
 1:	cmp	r0, #HVC_RESET_VECTORS
 	bne	1f
-ENTRY(__kvm_hyp_reset)
 	/* We're now in idmap, disable MMU */
 	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
 	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
@@ -151,7 +150,6 @@ ENTRY(__kvm_hyp_reset)
 exit:
 	eret
 ENDPROC(__kvm_handle_stub_hvc)
-ENDPROC(__kvm_hyp_reset)
 
 	.ltorg
 
-- 
2.11.0

[PATCH v5 24/34] ARM: KVM: Implement HVC_SOFT_RESTART in the init code

[Marc Zyngier]

Another missing stub hypercall is HVC_SOFT_RESTART. It turns out
that it is pretty easy to implement in terms of HVC_RESET_VECTORS
(since it needs to turn the MMU off).

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/init.S | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index fb336090ee9c..e53360dceb19 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -127,8 +127,22 @@ ENTRY(__kvm_handle_stub_hvc)
 	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
 	b	exit
 
+1:	cmp	r0, #HVC_SOFT_RESTART
+	bne	1f
+
+	/* The target is expected in r1 */
+	msr	ELR_hyp, r1
+	mrs	r0, cpsr
+	bic	r0, r0, #MODE_MASK
+	orr	r0, r0, #HYP_MODE
+THUMB(	orr	r0, r0, #PSR_T_BIT	)
+	msr	spsr_cxsf, r0
+	b	reset
+
 1:	cmp	r0, #HVC_RESET_VECTORS
 	bne	1f
+
+reset:
 	/* We're now in idmap, disable MMU */
 	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
 	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
-- 
2.11.0

[PATCH v5 24/34] ARM: KVM: Implement HVC_SOFT_RESTART in the init code

[Marc Zyngier]

Another missing stub hypercall is HVC_SOFT_RESTART. It turns out
that it is pretty easy to implement in terms of HVC_RESET_VECTORS
(since it needs to turn the MMU off).

Tested-by: Keerthy <j-keerthy@ti.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/init.S | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index fb336090ee9c..e53360dceb19 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -127,8 +127,22 @@ ENTRY(__kvm_handle_stub_hvc)
 	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
 	b	exit
 
+1:	cmp	r0, #HVC_SOFT_RESTART
+	bne	1f
+
+	/* The target is expected in r1 */
+	msr	ELR_hyp, r1
+	mrs	r0, cpsr
+	bic	r0, r0, #MODE_MASK
+	orr	r0, r0, #HYP_MODE
+THUMB(	orr	r0, r0, #PSR_T_BIT	)
+	msr	spsr_cxsf, r0
+	b	reset
+
 1:	cmp	r0, #HVC_RESET_VECTORS
 	bne	1f
+
+reset:
 	/* We're now in idmap, disable MMU */
 	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
 	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
-- 
2.11.0

[PATCH v5 25/34] ARM: KVM: Gracefully handle hyp-stubs being restored from under our feet

[Marc Zyngier]

Should kvm_reboot() be invoked while guest is running, an IPI
wil be issued, forcing the guest to exit and HYP being reset to
the stubs. We will then try to reenter the guest, only to get
an error (HVC_STUB_ERR).

This patch allows this case to be gracefully handled by exiting
the run loop.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_asm.h | 2 +-
 arch/arm/kvm/handle_exit.c     | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 7ccb6f1aac5b..df113302e637 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -33,7 +33,7 @@
 #define ARM_EXCEPTION_IRQ	  5
 #define ARM_EXCEPTION_FIQ	  6
 #define ARM_EXCEPTION_HVC	  7
-
+#define ARM_EXCEPTION_HYP_GONE	  HVC_STUB_ERR
 /*
  * The rr_lo_hi macro swaps a pair of registers depending on
  * current endianness. It is used in conjunction with ldrd and strd
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index 96af65a30d78..5fd7968cdae9 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -160,6 +160,14 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	case ARM_EXCEPTION_DATA_ABORT:
 		kvm_inject_vabt(vcpu);
 		return 1;
+	case ARM_EXCEPTION_HYP_GONE:
+		/*
+		 * HYP has been reset to the hyp-stub. This happens
+		 * when a guest is pre-empted by kvm_reboot()'s
+		 * shutdown call.
+		 */
+		run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+		return 0;
 	default:
 		kvm_pr_unimpl("Unsupported exception type: %d",
 			      exception_index);
-- 
2.11.0

[PATCH v5 25/34] ARM: KVM: Gracefully handle hyp-stubs being restored from under our feet

[Marc Zyngier]

Should kvm_reboot() be invoked while guest is running, an IPI
wil be issued, forcing the guest to exit and HYP being reset to
the stubs. We will then try to reenter the guest, only to get
an error (HVC_STUB_ERR).

This patch allows this case to be gracefully handled by exiting
the run loop.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_asm.h | 2 +-
 arch/arm/kvm/handle_exit.c     | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 7ccb6f1aac5b..df113302e637 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -33,7 +33,7 @@
 #define ARM_EXCEPTION_IRQ	  5
 #define ARM_EXCEPTION_FIQ	  6
 #define ARM_EXCEPTION_HVC	  7
-
+#define ARM_EXCEPTION_HYP_GONE	  HVC_STUB_ERR
 /*
  * The rr_lo_hi macro swaps a pair of registers depending on
  * current endianness. It is used in conjunction with ldrd and strd
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index 96af65a30d78..5fd7968cdae9 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -160,6 +160,14 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	case ARM_EXCEPTION_DATA_ABORT:
 		kvm_inject_vabt(vcpu);
 		return 1;
+	case ARM_EXCEPTION_HYP_GONE:
+		/*
+		 * HYP has been reset to the hyp-stub. This happens
+		 * when a guest is pre-empted by kvm_reboot()'s
+		 * shutdown call.
+		 */
+		run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+		return 0;
 	default:
 		kvm_pr_unimpl("Unsupported exception type: %d",
 			      exception_index);
-- 
2.11.0

[PATCH v5 26/34] arm/arm64: KVM: Use __hyp_reset_vectors() directly

[Marc Zyngier]

__cpu_reset_hyp_mode doesn't need to be passed any argument now,
as the hyp-stub implementations are self-contained, and is now
reduced to just calling __hyp_reset_vectors(). Let's drop the
wrapper and use the stub hypercall directly.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_host.h   | 6 ------
 arch/arm/kvm/arm.c                | 3 +--
 arch/arm64/include/asm/kvm_host.h | 6 ------
 3 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index adea30753185..d488b8866bc9 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -270,12 +270,6 @@ static inline void __cpu_init_stage2(void)
 	kvm_call_hyp(__init_stage2_translation);
 }
 
-static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
-					phys_addr_t phys_idmap_start)
-{
-	__hyp_reset_vectors();
-}
-
 static inline int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
 {
 	return 0;
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 96dba7cd8be7..57dd48d61796 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -1129,8 +1129,7 @@ static void cpu_hyp_reinit(void)
 static void cpu_hyp_reset(void)
 {
 	if (!is_kernel_in_hyp_mode())
-		__cpu_reset_hyp_mode(hyp_default_vectors,
-				     kvm_get_idmap_start());
+		__hyp_reset_vectors();
 }
 
 static void _kvm_arch_hardware_enable(void *discard)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 0355dd109956..578df18f66b7 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -362,12 +362,6 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 	__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
 }
 
-static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
-					phys_addr_t phys_idmap_start)
-{
-	__hyp_reset_vectors();
-}
-
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
-- 
2.11.0

[PATCH v5 26/34] arm/arm64: KVM: Use __hyp_reset_vectors() directly

[Marc Zyngier]

__cpu_reset_hyp_mode doesn't need to be passed any argument now,
as the hyp-stub implementations are self-contained, and is now
reduced to just calling __hyp_reset_vectors(). Let's drop the
wrapper and use the stub hypercall directly.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_host.h   | 6 ------
 arch/arm/kvm/arm.c                | 3 +--
 arch/arm64/include/asm/kvm_host.h | 6 ------
 3 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index adea30753185..d488b8866bc9 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -270,12 +270,6 @@ static inline void __cpu_init_stage2(void)
 	kvm_call_hyp(__init_stage2_translation);
 }
 
-static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
-					phys_addr_t phys_idmap_start)
-{
-	__hyp_reset_vectors();
-}
-
 static inline int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
 {
 	return 0;
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 96dba7cd8be7..57dd48d61796 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -1129,8 +1129,7 @@ static void cpu_hyp_reinit(void)
 static void cpu_hyp_reset(void)
 {
 	if (!is_kernel_in_hyp_mode())
-		__cpu_reset_hyp_mode(hyp_default_vectors,
-				     kvm_get_idmap_start());
+		__hyp_reset_vectors();
 }
 
 static void _kvm_arch_hardware_enable(void *discard)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 0355dd109956..578df18f66b7 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -362,12 +362,6 @@ static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
 	__kvm_call_hyp((void *)pgd_ptr, hyp_stack_ptr, vector_ptr);
 }
 
-static inline void __cpu_reset_hyp_mode(unsigned long vector_ptr,
-					phys_addr_t phys_idmap_start)
-{
-	__hyp_reset_vectors();
-}
-
 static inline void kvm_arch_hardware_unsetup(void) {}
 static inline void kvm_arch_sync_events(struct kvm *kvm) {}
 static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
-- 
2.11.0

[PATCH v5 27/34] arm/arm64: KVM: Remove kvm_get_idmap_start

[Marc Zyngier]

With __cpu_reset_hyp_mode having become fairly dumb, there is no
need for kvm_get_idmap_start anymore.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_mmu.h   | 1 -
 arch/arm/kvm/mmu.c               | 5 -----
 arch/arm64/include/asm/kvm_mmu.h | 1 -
 3 files changed, 7 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 95f38dcd611d..fa6f2174276b 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -56,7 +56,6 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
-phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 962616fd4ddd..59f555b64dec 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1674,11 +1674,6 @@ phys_addr_t kvm_get_idmap_vector(void)
 	return hyp_idmap_vector;
 }
 
-phys_addr_t kvm_get_idmap_start(void)
-{
-	return hyp_idmap_start;
-}
-
 static int kvm_map_idmap_text(pgd_t *pgd)
 {
 	int err;
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index ed1246014901..91d93a5d8fd3 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -155,7 +155,6 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
-phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
-- 
2.11.0

[PATCH v5 27/34] arm/arm64: KVM: Remove kvm_get_idmap_start

[Marc Zyngier]

With __cpu_reset_hyp_mode having become fairly dumb, there is no
need for kvm_get_idmap_start anymore.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/kvm_mmu.h   | 1 -
 arch/arm/kvm/mmu.c               | 5 -----
 arch/arm64/include/asm/kvm_mmu.h | 1 -
 3 files changed, 7 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 95f38dcd611d..fa6f2174276b 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -56,7 +56,6 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
-phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 962616fd4ddd..59f555b64dec 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1674,11 +1674,6 @@ phys_addr_t kvm_get_idmap_vector(void)
 	return hyp_idmap_vector;
 }
 
-phys_addr_t kvm_get_idmap_start(void)
-{
-	return hyp_idmap_start;
-}
-
 static int kvm_map_idmap_text(pgd_t *pgd)
 {
 	int err;
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index ed1246014901..91d93a5d8fd3 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -155,7 +155,6 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu);
 
 phys_addr_t kvm_mmu_get_httbr(void);
 phys_addr_t kvm_get_idmap_vector(void);
-phys_addr_t kvm_get_idmap_start(void);
 int kvm_mmu_init(void);
 void kvm_clear_hyp_idmap(void);
 
-- 
2.11.0

[PATCH v5 28/34] arm/arm64: KVM: Use HVC_RESET_VECTORS to reinit HYP mode

[Marc Zyngier]

Instead of trying to compare the value given by __hyp_get_vectors(),
which doesn't offer any real guarantee to be the stub's address, use
HVC_RESET_VECTORS to make sure we're in a sane state to reinstall
KVM across PM events.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/arm.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 57dd48d61796..cbd3a3150090 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -53,7 +53,6 @@ __asm__(".arch_extension	virt");
 
 static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
 static kvm_cpu_context_t __percpu *kvm_host_cpu_state;
-static unsigned long hyp_default_vectors;
 
 /* Per-CPU variable containing the currently running vcpu. */
 static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);
@@ -1112,8 +1111,16 @@ static void cpu_init_hyp_mode(void *dummy)
 	kvm_arm_init_debug();
 }
 
+static void cpu_hyp_reset(void)
+{
+	if (!is_kernel_in_hyp_mode())
+		__hyp_reset_vectors();
+}
+
 static void cpu_hyp_reinit(void)
 {
+	cpu_hyp_reset();
+
 	if (is_kernel_in_hyp_mode()) {
 		/*
 		 * __cpu_init_stage2() is safe to call even if the PM
@@ -1121,17 +1128,10 @@ static void cpu_hyp_reinit(void)
 		 */
 		__cpu_init_stage2();
 	} else {
-		if (__hyp_get_vectors() == hyp_default_vectors)
-			cpu_init_hyp_mode(NULL);
+		cpu_init_hyp_mode(NULL);
 	}
 }
 
-static void cpu_hyp_reset(void)
-{
-	if (!is_kernel_in_hyp_mode())
-		__hyp_reset_vectors();
-}
-
 static void _kvm_arch_hardware_enable(void *discard)
 {
 	if (!__this_cpu_read(kvm_arm_hardware_enabled)) {
@@ -1315,12 +1315,6 @@ static int init_hyp_mode(void)
 		goto out_err;
 
 	/*
-	 * It is probably enough to obtain the default on one
-	 * CPU. It's unlikely to be different on the others.
-	 */
-	hyp_default_vectors = __hyp_get_vectors();
-
-	/*
 	 * Allocate stack pages for Hypervisor-mode
 	 */
 	for_each_possible_cpu(cpu) {
-- 
2.11.0

[PATCH v5 28/34] arm/arm64: KVM: Use HVC_RESET_VECTORS to reinit HYP mode

[Marc Zyngier]

Instead of trying to compare the value given by __hyp_get_vectors(),
which doesn't offer any real guarantee to be the stub's address, use
HVC_RESET_VECTORS to make sure we're in a sane state to reinstall
KVM across PM events.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/arm.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 57dd48d61796..cbd3a3150090 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -53,7 +53,6 @@ __asm__(".arch_extension	virt");
 
 static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
 static kvm_cpu_context_t __percpu *kvm_host_cpu_state;
-static unsigned long hyp_default_vectors;
 
 /* Per-CPU variable containing the currently running vcpu. */
 static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);
@@ -1112,8 +1111,16 @@ static void cpu_init_hyp_mode(void *dummy)
 	kvm_arm_init_debug();
 }
 
+static void cpu_hyp_reset(void)
+{
+	if (!is_kernel_in_hyp_mode())
+		__hyp_reset_vectors();
+}
+
 static void cpu_hyp_reinit(void)
 {
+	cpu_hyp_reset();
+
 	if (is_kernel_in_hyp_mode()) {
 		/*
 		 * __cpu_init_stage2() is safe to call even if the PM
@@ -1121,17 +1128,10 @@ static void cpu_hyp_reinit(void)
 		 */
 		__cpu_init_stage2();
 	} else {
-		if (__hyp_get_vectors() == hyp_default_vectors)
-			cpu_init_hyp_mode(NULL);
+		cpu_init_hyp_mode(NULL);
 	}
 }
 
-static void cpu_hyp_reset(void)
-{
-	if (!is_kernel_in_hyp_mode())
-		__hyp_reset_vectors();
-}
-
 static void _kvm_arch_hardware_enable(void *discard)
 {
 	if (!__this_cpu_read(kvm_arm_hardware_enabled)) {
@@ -1315,12 +1315,6 @@ static int init_hyp_mode(void)
 		goto out_err;
 
 	/*
-	 * It is probably enough to obtain the default on one
-	 * CPU. It's unlikely to be different on the others.
-	 */
-	hyp_default_vectors = __hyp_get_vectors();
-
-	/*
 	 * Allocate stack pages for Hypervisor-mode
 	 */
 	for_each_possible_cpu(cpu) {
-- 
2.11.0

[PATCH v5 29/34] ARM: decompressor: Remove __hyp_get_vectors usage

[Marc Zyngier]

When the compressed image needs to be relocated to avoid being
overwritten by the decompression process, we need to relocate
the hyp vectors as well so that we can find them once the
decompression has taken effect.

For that, we perform the following calculation:
	u32 v = __hyp_get_vectors();
	v += offset;
	__hyp_set_vectors(v);

But we're guaranteed that the initial value of v as returned by
__hyp_get_vectors is always __hyp_stub_vectors, because we have
just set it by calling __hyp_stub_install.

So let's remove the use of __hyp_get_vectors, and directly use
__hyp_stub_vectors instead.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/boot/compressed/head.S | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 9150f9732785..7c711ba61417 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -422,7 +422,17 @@ dtb_check_done:
 		cmp	r0, #HYP_MODE
 		bne	1f
 
-		bl	__hyp_get_vectors
+		/*
+		 * Compute the address of the hyp vectors after relocation.
+		 * This requires some arithmetic since we cannot directly
+		 * reference __hyp_stub_vectors in a PC-relative way.
+		 * Call __hyp_set_vectors with the new address so that we
+		 * can HVC again after the copy.
+		 */
+0:		adr	r0, 0b
+		movw	r1, #:lower16:__hyp_stub_vectors - 0b
+		movt	r1, #:upper16:__hyp_stub_vectors - 0b
+		add	r0, r0, r1
 		sub	r0, r0, r5
 		add	r0, r0, r10
 		bl	__hyp_set_vectors
-- 
2.11.0

[PATCH v5 29/34] ARM: decompressor: Remove __hyp_get_vectors usage

[Marc Zyngier]

When the compressed image needs to be relocated to avoid being
overwritten by the decompression process, we need to relocate
the hyp vectors as well so that we can find them once the
decompression has taken effect.

For that, we perform the following calculation:
	u32 v = __hyp_get_vectors();
	v += offset;
	__hyp_set_vectors(v);

But we're guaranteed that the initial value of v as returned by
__hyp_get_vectors is always __hyp_stub_vectors, because we have
just set it by calling __hyp_stub_install.

So let's remove the use of __hyp_get_vectors, and directly use
__hyp_stub_vectors instead.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/boot/compressed/head.S | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 9150f9732785..7c711ba61417 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -422,7 +422,17 @@ dtb_check_done:
 		cmp	r0, #HYP_MODE
 		bne	1f
 
-		bl	__hyp_get_vectors
+		/*
+		 * Compute the address of the hyp vectors after relocation.
+		 * This requires some arithmetic since we cannot directly
+		 * reference __hyp_stub_vectors in a PC-relative way.
+		 * Call __hyp_set_vectors with the new address so that we
+		 * can HVC again after the copy.
+		 */
+0:		adr	r0, 0b
+		movw	r1, #:lower16:__hyp_stub_vectors - 0b
+		movt	r1, #:upper16:__hyp_stub_vectors - 0b
+		add	r0, r0, r1
 		sub	r0, r0, r5
 		add	r0, r0, r10
 		bl	__hyp_set_vectors
-- 
2.11.0

[PATCH v5 30/34] ARM: hyp-stub/KVM: Kill __hyp_get_vectors

[Marc Zyngier]

Nobody is using __hyp_get_vectors anymore, so let's remove both
implementations (hyp-stub and KVM).

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h | 10 ++++------
 arch/arm/kernel/hyp-stub.S  | 13 +------------
 arch/arm/kvm/init.S         |  7 +------
 arch/arm/kvm/interrupts.S   |  4 ----
 4 files changed, 6 insertions(+), 28 deletions(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 663adc09c918..141144f333a2 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -53,7 +53,6 @@ static inline void sync_boot_mode(void)
 }
 
 void __hyp_set_vectors(unsigned long phys_vector_base);
-unsigned long __hyp_get_vectors(void);
 void __hyp_reset_vectors(void);
 #else
 #define __boot_cpu_mode	(SVC_MODE)
@@ -99,12 +98,11 @@ extern char __hyp_text_end[];
 
 /* Only assembly code should need those */
 
-#define HVC_GET_VECTORS 0
-#define HVC_SET_VECTORS 1
-#define HVC_SOFT_RESTART 2
-#define HVC_RESET_VECTORS 3
+#define HVC_SET_VECTORS 0
+#define HVC_SOFT_RESTART 1
+#define HVC_RESET_VECTORS 2
 
-#define HVC_STUB_HCALL_NR 4
+#define HVC_STUB_HCALL_NR 3
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 675c50f5cb5c..918c64f17128 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -202,12 +202,7 @@ ARM_BE8(orr	r7, r7, #(1 << 25))     @ HSCTLR.EE
 ENDPROC(__hyp_stub_install_secondary)
 
 __hyp_stub_do_trap:
-	teq	r0, #HVC_GET_VECTORS
-	bne	1f
-	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	b	__hyp_stub_exit
-
-1:	teq	r0, #HVC_SET_VECTORS
+	teq	r0, #HVC_SET_VECTORS
 	bne	1f
 	mcr	p15, 4, r1, c12, c0, 0	@ set HVBAR
 	b	__hyp_stub_exit
@@ -247,12 +242,6 @@ ENDPROC(__hyp_stub_do_trap)
  * so you will need to set that to something sensible at the new hypervisor's
  * initialisation entry point.
  */
-ENTRY(__hyp_get_vectors)
-	mov	r0, #HVC_GET_VECTORS
-	__HVC(0)
-	ret	lr
-ENDPROC(__hyp_get_vectors)
-
 ENTRY(__hyp_set_vectors)
 	mov	r1, r0
 	mov	r0, #HVC_SET_VECTORS
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index e53360dceb19..87bcd7ae4552 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -122,12 +122,7 @@ __do_hyp_init:
 	eret
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	r0, #HVC_GET_VECTORS
-	bne	1f
-	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	b	exit
-
-1:	cmp	r0, #HVC_SOFT_RESTART
+	cmp	r0, #HVC_SOFT_RESTART
 	bne	1f
 
 	/* The target is expected in r1 */
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index b1bd316f14c0..80a1d6cd261c 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -37,10 +37,6 @@
  * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
  * passed in r0 (strictly 32bit).
  *
- * A function pointer with a value of 0xffffffff has a special meaning,
- * and is used to implement __hyp_get_vectors in the same way as in
- * arch/arm/kernel/hyp_stub.S.
- *
  * The calling convention follows the standard AAPCS:
  *   r0 - r3: caller save
  *   r12:     caller save
-- 
2.11.0

[PATCH v5 30/34] ARM: hyp-stub/KVM: Kill __hyp_get_vectors

[Marc Zyngier]

Nobody is using __hyp_get_vectors anymore, so let's remove both
implementations (hyp-stub and KVM).

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/include/asm/virt.h | 10 ++++------
 arch/arm/kernel/hyp-stub.S  | 13 +------------
 arch/arm/kvm/init.S         |  7 +------
 arch/arm/kvm/interrupts.S   |  4 ----
 4 files changed, 6 insertions(+), 28 deletions(-)

diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
index 663adc09c918..141144f333a2 100644
--- a/arch/arm/include/asm/virt.h
+++ b/arch/arm/include/asm/virt.h
@@ -53,7 +53,6 @@ static inline void sync_boot_mode(void)
 }
 
 void __hyp_set_vectors(unsigned long phys_vector_base);
-unsigned long __hyp_get_vectors(void);
 void __hyp_reset_vectors(void);
 #else
 #define __boot_cpu_mode	(SVC_MODE)
@@ -99,12 +98,11 @@ extern char __hyp_text_end[];
 
 /* Only assembly code should need those */
 
-#define HVC_GET_VECTORS 0
-#define HVC_SET_VECTORS 1
-#define HVC_SOFT_RESTART 2
-#define HVC_RESET_VECTORS 3
+#define HVC_SET_VECTORS 0
+#define HVC_SOFT_RESTART 1
+#define HVC_RESET_VECTORS 2
 
-#define HVC_STUB_HCALL_NR 4
+#define HVC_STUB_HCALL_NR 3
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 675c50f5cb5c..918c64f17128 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -202,12 +202,7 @@ ARM_BE8(orr	r7, r7, #(1 << 25))     @ HSCTLR.EE
 ENDPROC(__hyp_stub_install_secondary)
 
 __hyp_stub_do_trap:
-	teq	r0, #HVC_GET_VECTORS
-	bne	1f
-	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	b	__hyp_stub_exit
-
-1:	teq	r0, #HVC_SET_VECTORS
+	teq	r0, #HVC_SET_VECTORS
 	bne	1f
 	mcr	p15, 4, r1, c12, c0, 0	@ set HVBAR
 	b	__hyp_stub_exit
@@ -247,12 +242,6 @@ ENDPROC(__hyp_stub_do_trap)
  * so you will need to set that to something sensible@the new hypervisor's
  * initialisation entry point.
  */
-ENTRY(__hyp_get_vectors)
-	mov	r0, #HVC_GET_VECTORS
-	__HVC(0)
-	ret	lr
-ENDPROC(__hyp_get_vectors)
-
 ENTRY(__hyp_set_vectors)
 	mov	r1, r0
 	mov	r0, #HVC_SET_VECTORS
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index e53360dceb19..87bcd7ae4552 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -122,12 +122,7 @@ __do_hyp_init:
 	eret
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	r0, #HVC_GET_VECTORS
-	bne	1f
-	mrc	p15, 4, r0, c12, c0, 0	@ get HVBAR
-	b	exit
-
-1:	cmp	r0, #HVC_SOFT_RESTART
+	cmp	r0, #HVC_SOFT_RESTART
 	bne	1f
 
 	/* The target is expected in r1 */
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index b1bd316f14c0..80a1d6cd261c 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -37,10 +37,6 @@
  * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c).  Return values are
  * passed in r0 (strictly 32bit).
  *
- * A function pointer with a value of 0xffffffff has a special meaning,
- * and is used to implement __hyp_get_vectors in the same way as in
- * arch/arm/kernel/hyp_stub.S.
- *
  * The calling convention follows the standard AAPCS:
  *   r0 - r3: caller save
  *   r12:     caller save
-- 
2.11.0

[PATCH v5 31/34] arm64: hyp-stub/KVM: Kill __hyp_get_vectors

[Marc Zyngier]

Nobody is using __hyp_get_vectors anymore, so let's remove both
implementations (hyp-stub and KVM).

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h | 12 ++++--------
 arch/arm64/kernel/hyp-stub.S  | 13 +------------
 arch/arm64/kvm/hyp-init.S     |  7 +------
 arch/arm64/kvm/hyp.S          |  2 +-
 4 files changed, 7 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 435514c52b0f..c5f89442785c 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -29,28 +29,25 @@
  * indirection of a function call (as implemented in hyp-stub.S).
  */
 
-/* HVC_GET_VECTORS - Return the value of the vbar_el2 register. */
-#define HVC_GET_VECTORS 0
-
 /*
  * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
  *
  * @x1: Physical address of the new vector table.
  */
-#define HVC_SET_VECTORS 1
+#define HVC_SET_VECTORS 0
 
 /*
  * HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
  */
-#define HVC_SOFT_RESTART 2
+#define HVC_SOFT_RESTART 1
 
 /*
  * HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
  */
-#define HVC_RESET_VECTORS 3
+#define HVC_RESET_VECTORS 2
 
 /* Max number of HYP stub hypercalls */
-#define HVC_STUB_HCALL_NR 4
+#define HVC_STUB_HCALL_NR 3
 
 /* Error returned when an invalid stub number is passed into x0 */
 #define HVC_STUB_ERR	0xbadca11
@@ -77,7 +74,6 @@
 extern u32 __boot_cpu_mode[2];
 
 void __hyp_set_vectors(phys_addr_t phys_vector_base);
-phys_addr_t __hyp_get_vectors(void);
 void __hyp_reset_vectors(void);
 
 /* Reports the availability of HYP mode */
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 8226fd90f73c..d55604d91e33 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -55,12 +55,7 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	cmp	x0, #HVC_GET_VECTORS
-	b.ne	1f
-	mrs	x0, vbar_el2
-	b	9f
-
-1:	cmp	x0, #HVC_SET_VECTORS
+	cmp	x0, #HVC_SET_VECTORS
 	b.ne	2f
 	msr	vbar_el2, x1
 	b	9f
@@ -118,12 +113,6 @@ ENDPROC(\label)
  * initialisation entry point.
  */
 
-ENTRY(__hyp_get_vectors)
-	mov	x0, #HVC_GET_VECTORS
-	hvc	#0
-	ret
-ENDPROC(__hyp_get_vectors)
-
 ENTRY(__hyp_set_vectors)
 	mov	x1, x0
 	mov	x0, #HVC_SET_VECTORS
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 0ad34fd6d2fc..3734e6315cd7 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -124,12 +124,7 @@ __do_hyp_init:
 ENDPROC(__kvm_hyp_init)
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	x0, #HVC_GET_VECTORS
-	b.ne	1f
-	mrs	x0, vbar_el2
-	b	exit
-
-1:	cmp	x0, #HVC_SOFT_RESTART
+	cmp	x0, #HVC_SOFT_RESTART
 	b.ne	1f
 
 	/* This is where we're about to jump, staying at EL2 */
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index f6f20b58d65a..952f6cb9cf72 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -36,7 +36,7 @@
  * passed in x0.
  *
  * A function pointer with a value less than 0xfff has a special meaning,
- * and is used to implement __hyp_get_vectors in the same way as in
+ * and is used to implement hyp stubs in the same way as in
  * arch/arm64/kernel/hyp_stub.S.
  */
 ENTRY(__kvm_call_hyp)
-- 
2.11.0

[PATCH v5 31/34] arm64: hyp-stub/KVM: Kill __hyp_get_vectors

[Marc Zyngier]

Nobody is using __hyp_get_vectors anymore, so let's remove both
implementations (hyp-stub and KVM).

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h | 12 ++++--------
 arch/arm64/kernel/hyp-stub.S  | 13 +------------
 arch/arm64/kvm/hyp-init.S     |  7 +------
 arch/arm64/kvm/hyp.S          |  2 +-
 4 files changed, 7 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 435514c52b0f..c5f89442785c 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -29,28 +29,25 @@
  * indirection of a function call (as implemented in hyp-stub.S).
  */
 
-/* HVC_GET_VECTORS - Return the value of the vbar_el2 register. */
-#define HVC_GET_VECTORS 0
-
 /*
  * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
  *
  * @x1: Physical address of the new vector table.
  */
-#define HVC_SET_VECTORS 1
+#define HVC_SET_VECTORS 0
 
 /*
  * HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
  */
-#define HVC_SOFT_RESTART 2
+#define HVC_SOFT_RESTART 1
 
 /*
  * HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
  */
-#define HVC_RESET_VECTORS 3
+#define HVC_RESET_VECTORS 2
 
 /* Max number of HYP stub hypercalls */
-#define HVC_STUB_HCALL_NR 4
+#define HVC_STUB_HCALL_NR 3
 
 /* Error returned when an invalid stub number is passed into x0 */
 #define HVC_STUB_ERR	0xbadca11
@@ -77,7 +74,6 @@
 extern u32 __boot_cpu_mode[2];
 
 void __hyp_set_vectors(phys_addr_t phys_vector_base);
-phys_addr_t __hyp_get_vectors(void);
 void __hyp_reset_vectors(void);
 
 /* Reports the availability of HYP mode */
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 8226fd90f73c..d55604d91e33 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -55,12 +55,7 @@ ENDPROC(__hyp_stub_vectors)
 	.align 11
 
 el1_sync:
-	cmp	x0, #HVC_GET_VECTORS
-	b.ne	1f
-	mrs	x0, vbar_el2
-	b	9f
-
-1:	cmp	x0, #HVC_SET_VECTORS
+	cmp	x0, #HVC_SET_VECTORS
 	b.ne	2f
 	msr	vbar_el2, x1
 	b	9f
@@ -118,12 +113,6 @@ ENDPROC(\label)
  * initialisation entry point.
  */
 
-ENTRY(__hyp_get_vectors)
-	mov	x0, #HVC_GET_VECTORS
-	hvc	#0
-	ret
-ENDPROC(__hyp_get_vectors)
-
 ENTRY(__hyp_set_vectors)
 	mov	x1, x0
 	mov	x0, #HVC_SET_VECTORS
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 0ad34fd6d2fc..3734e6315cd7 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -124,12 +124,7 @@ __do_hyp_init:
 ENDPROC(__kvm_hyp_init)
 
 ENTRY(__kvm_handle_stub_hvc)
-	cmp	x0, #HVC_GET_VECTORS
-	b.ne	1f
-	mrs	x0, vbar_el2
-	b	exit
-
-1:	cmp	x0, #HVC_SOFT_RESTART
+	cmp	x0, #HVC_SOFT_RESTART
 	b.ne	1f
 
 	/* This is where we're about to jump, staying at EL2 */
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index f6f20b58d65a..952f6cb9cf72 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -36,7 +36,7 @@
  * passed in x0.
  *
  * A function pointer with a value less than 0xfff has a special meaning,
- * and is used to implement __hyp_get_vectors in the same way as in
+ * and is used to implement hyp stubs in the same way as in
  * arch/arm64/kernel/hyp_stub.S.
  */
 ENTRY(__kvm_call_hyp)
-- 
2.11.0

[PATCH v5 32/34] arm64: hyp-stub: Zero x0 on successful stub handling

[Marc Zyngier]

We now return HVC_STUB_ERR when a stub hypercall fails, but we
leave whatever was in x0 on success. Zeroing it on return seems
like a good idea.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kernel/hyp-stub.S | 4 +++-
 arch/arm64/kvm/hyp-init.S    | 6 +++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d55604d91e33..e1261fbaa374 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -73,8 +73,10 @@ el1_sync:
 
 	/* Someone called kvm_call_hyp() against the hyp-stub... */
 	ldr	x0, =HVC_STUB_ERR
+	eret
 
-9:	eret
+9:	mov	x0, xzr
+	eret
 ENDPROC(el1_sync)
 
 .macro invalid_vector	label
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 3734e6315cd7..839425c24b1c 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -154,13 +154,13 @@ reset:
 	/* Install stub vectors */
 	adr_l	x5, __hyp_stub_vectors
 	msr	vbar_el2, x5
-	b	exit
+	mov	x0, xzr
+	eret
 
 1:	/* Bad stub call */
 	ldr	x0, =HVC_STUB_ERR
-
-exit:
 	eret
+
 ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
-- 
2.11.0

[PATCH v5 32/34] arm64: hyp-stub: Zero x0 on successful stub handling

[Marc Zyngier]

We now return HVC_STUB_ERR when a stub hypercall fails, but we
leave whatever was in x0 on success. Zeroing it on return seems
like a good idea.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kernel/hyp-stub.S | 4 +++-
 arch/arm64/kvm/hyp-init.S    | 6 +++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d55604d91e33..e1261fbaa374 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -73,8 +73,10 @@ el1_sync:
 
 	/* Someone called kvm_call_hyp() against the hyp-stub... */
 	ldr	x0, =HVC_STUB_ERR
+	eret
 
-9:	eret
+9:	mov	x0, xzr
+	eret
 ENDPROC(el1_sync)
 
 .macro invalid_vector	label
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 3734e6315cd7..839425c24b1c 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -154,13 +154,13 @@ reset:
 	/* Install stub vectors */
 	adr_l	x5, __hyp_stub_vectors
 	msr	vbar_el2, x5
-	b	exit
+	mov	x0, xzr
+	eret
 
 1:	/* Bad stub call */
 	ldr	x0, =HVC_STUB_ERR
-
-exit:
 	eret
+
 ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
-- 
2.11.0

[PATCH v5 33/34] ARM: hyp-stub: Zero r0 on successful stub handling

[Marc Zyngier]

We now return HVC_STUB_ERR when a stub hypercall fails, but we
leave whatever was in r0 on success. Zeroing it on return seems
like a good idea.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kernel/hyp-stub.S | 2 ++
 arch/arm/kvm/init.S        | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 918c64f17128..d8523cc47a54 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -215,8 +215,10 @@ __hyp_stub_do_trap:
 	beq	__hyp_stub_exit
 
 	ldr	r0, =HVC_STUB_ERR
+	__ERET
 
 __hyp_stub_exit:
+	mov	r0, #0
 	__ERET
 ENDPROC(__hyp_stub_do_trap)
 
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 87bcd7ae4552..570ed4a9c261 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -155,8 +155,10 @@ reset:
 	b	exit
 
 1:	ldr	r0, =HVC_STUB_ERR
+	eret
 
 exit:
+	mov	r0, #0
 	eret
 ENDPROC(__kvm_handle_stub_hvc)
 
-- 
2.11.0

[PATCH v5 33/34] ARM: hyp-stub: Zero r0 on successful stub handling

[Marc Zyngier]

We now return HVC_STUB_ERR when a stub hypercall fails, but we
leave whatever was in r0 on success. Zeroing it on return seems
like a good idea.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kernel/hyp-stub.S | 2 ++
 arch/arm/kvm/init.S        | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 918c64f17128..d8523cc47a54 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -215,8 +215,10 @@ __hyp_stub_do_trap:
 	beq	__hyp_stub_exit
 
 	ldr	r0, =HVC_STUB_ERR
+	__ERET
 
 __hyp_stub_exit:
+	mov	r0, #0
 	__ERET
 ENDPROC(__hyp_stub_do_trap)
 
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 87bcd7ae4552..570ed4a9c261 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -155,8 +155,10 @@ reset:
 	b	exit
 
 1:	ldr	r0, =HVC_STUB_ERR
+	eret
 
 exit:
+	mov	r0, #0
 	eret
 ENDPROC(__kvm_handle_stub_hvc)
 
-- 
2.11.0

[PATCH v5 34/34] arm/arm64: Add hyp-stub API documentation

[Marc Zyngier]

In order to help people understanding the hyp-stub API that exists
between the host kernel and the hypervisor mode (whether a hypervisor
has been installed or not), let's document said API.

As with any form of documentation, I expect it to become obsolete
and completely misleading within 20 minutes after having being merged.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 Documentation/virtual/kvm/arm/hyp-abi.txt | 53 +++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt

diff --git a/Documentation/virtual/kvm/arm/hyp-abi.txt b/Documentation/virtual/kvm/arm/hyp-abi.txt
new file mode 100644
index 000000000000..a20a0bee268d
--- /dev/null
+++ b/Documentation/virtual/kvm/arm/hyp-abi.txt
@@ -0,0 +1,53 @@
+* Internal ABI between the kernel and HYP
+
+This file documents the interaction between the Linux kernel and the
+hypervisor layer when running Linux as a hypervisor (for example
+KVM). It doesn't cover the interaction of the kernel with the
+hypervisor when running as a guest (under Xen, KVM or any other
+hypervisor), or any hypervisor-specific interaction when the kernel is
+used as a host.
+
+On arm and arm64 (without VHE), the kernel doesn't run in hypervisor
+mode, but still needs to interact with it, allowing a built-in
+hypervisor to be either installed or torn down.
+
+In order to achieve this, the kernel must be booted at HYP (arm) or
+EL2 (arm64), allowing it to install a set of stubs before dropping to
+SVC/EL1. These stubs are accessible by using a 'hvc #0' instruction,
+and only act on individual CPUs.
+
+Unless specified otherwise, any built-in hypervisor must implement
+these functions (see arch/arm{,64}/include/asm/virt.h):
+
+* r0/x0 = HVC_SET_VECTORS
+  r1/x1 = vectors
+
+  Set HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
+  must be a physical address, and respect the alignment requirements
+  of the architecture. Only implemented by the initial stubs, not by
+  Linux hypervisors.
+
+* r0/x0 = HVC_RESET_VECTORS
+
+  Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
+  stubs' exception vector value. This effectively disables an existing
+  hypervisor.
+
+* r0/x0 = HVC_SOFT_RESTART
+  r1/x1 = restart address
+  x2 = x0's value when entering the next payload (arm64)
+  x3 = x1's value when entering the next payload (arm64)
+  x4 = x2's value when entering the next payload (arm64)
+
+  Mask all exceptions, disable the MMU, move the arguments into place
+  (arm64 only), and jump to the restart address while at HYP/EL2. This
+  hypercall is not expected to return to its caller.
+
+Any other value of r0/x0 triggers a hypervisor-specific handling,
+which is not documented here.
+
+The return value of a stub hypercall is held by r0/x0, and is 0 on
+success, and HVC_STUB_ERR on error. A stub hypercall is allowed to
+clobber any of the caller-saved registers (x0-x18 on arm64, r0-r3 and
+ip on arm). It is thus recommended to use a function call to perform
+the hypercall.
-- 
2.11.0

[PATCH v5 34/34] arm/arm64: Add hyp-stub API documentation

[Marc Zyngier]

In order to help people understanding the hyp-stub API that exists
between the host kernel and the hypervisor mode (whether a hypervisor
has been installed or not), let's document said API.

As with any form of documentation, I expect it to become obsolete
and completely misleading within 20 minutes after having being merged.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 Documentation/virtual/kvm/arm/hyp-abi.txt | 53 +++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt

diff --git a/Documentation/virtual/kvm/arm/hyp-abi.txt b/Documentation/virtual/kvm/arm/hyp-abi.txt
new file mode 100644
index 000000000000..a20a0bee268d
--- /dev/null
+++ b/Documentation/virtual/kvm/arm/hyp-abi.txt
@@ -0,0 +1,53 @@
+* Internal ABI between the kernel and HYP
+
+This file documents the interaction between the Linux kernel and the
+hypervisor layer when running Linux as a hypervisor (for example
+KVM). It doesn't cover the interaction of the kernel with the
+hypervisor when running as a guest (under Xen, KVM or any other
+hypervisor), or any hypervisor-specific interaction when the kernel is
+used as a host.
+
+On arm and arm64 (without VHE), the kernel doesn't run in hypervisor
+mode, but still needs to interact with it, allowing a built-in
+hypervisor to be either installed or torn down.
+
+In order to achieve this, the kernel must be booted at HYP (arm) or
+EL2 (arm64), allowing it to install a set of stubs before dropping to
+SVC/EL1. These stubs are accessible by using a 'hvc #0' instruction,
+and only act on individual CPUs.
+
+Unless specified otherwise, any built-in hypervisor must implement
+these functions (see arch/arm{,64}/include/asm/virt.h):
+
+* r0/x0 = HVC_SET_VECTORS
+  r1/x1 = vectors
+
+  Set HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
+  must be a physical address, and respect the alignment requirements
+  of the architecture. Only implemented by the initial stubs, not by
+  Linux hypervisors.
+
+* r0/x0 = HVC_RESET_VECTORS
+
+  Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
+  stubs' exception vector value. This effectively disables an existing
+  hypervisor.
+
+* r0/x0 = HVC_SOFT_RESTART
+  r1/x1 = restart address
+  x2 = x0's value when entering the next payload (arm64)
+  x3 = x1's value when entering the next payload (arm64)
+  x4 = x2's value when entering the next payload (arm64)
+
+  Mask all exceptions, disable the MMU, move the arguments into place
+  (arm64 only), and jump to the restart address while at HYP/EL2. This
+  hypercall is not expected to return to its caller.
+
+Any other value of r0/x0 triggers a hypervisor-specific handling,
+which is not documented here.
+
+The return value of a stub hypercall is held by r0/x0, and is 0 on
+success, and HVC_STUB_ERR on error. A stub hypercall is allowed to
+clobber any of the caller-saved registers (x0-x18 on arm64, r0-r3 and
+ip on arm). It is thus recommended to use a function call to perform
+the hypercall.
-- 
2.11.0

Re: [PATCH v5 00/34] arm/arm64: KVM: Rework the hyp-stub API

[Christoffer Dall]

Hi Marc,

On Mon, Apr 03, 2017 at 07:37:33PM +0100, Marc Zyngier wrote:
> As noticed by RMK in this thread[1], the hyp-stub API on 32bit ARM
> could do with some TLC (it cannot perform a soft-restart at HYP, and
> has holes in the hyp-stub support in a number of places). In general,
> it would be desirable for the 32bit behaviour to align on 64bit, if
> only to ease maintenance.
> 
> This series implements the following:
> - Add HVC_[GS]ET_VECTORS and HVC_SOFT_RESTART to the 32bit code
> - Add HVC_RESET_VECTORS to both arm and arm64, removing the need for
>   __hyp_reset_vectors
> - Implement add the stub entry points in the KVM init code, which
>   didn't implement any so far
> - Convert the HYP code to use the init code stubs directly
> - Some general cleanup as a result of these changes (which includes
>   killing HVC_GET_VECTORS)
> - Add some API documentation that covers the above
> 
> Patches 14 to 16 would be better squashed into 12 and 13, but I've
> kept them separate so that I can take the blame for everything I've
> broken.
> 
> I've tested this on arm (Cubietruck, Jetson TK1) and arm64 (Seattle),
> both as host and guest. Keerthy has been kind enough to test the 32bit
> code on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473472.html
> 
> * From v4:
>   - Added a standard return value on stub hypercall failure
>   - Zero r0/x0 on successful hypercall
>   - Make 32bit ARM resistant to kvm_reboot while executing a guest
>   - Update documentation to reflect the calling convention expectations
>   - Added Acks from Catalin
>   - Rebased on 4.11-rc5

Thanks for doing the changes.

I have applied your patches to kvmarm/queue.

-Christoffer

[PATCH v5 00/34] arm/arm64: KVM: Rework the hyp-stub API

[Christoffer Dall]

Hi Marc,

On Mon, Apr 03, 2017 at 07:37:33PM +0100, Marc Zyngier wrote:
> As noticed by RMK in this thread[1], the hyp-stub API on 32bit ARM
> could do with some TLC (it cannot perform a soft-restart at HYP, and
> has holes in the hyp-stub support in a number of places). In general,
> it would be desirable for the 32bit behaviour to align on 64bit, if
> only to ease maintenance.
> 
> This series implements the following:
> - Add HVC_[GS]ET_VECTORS and HVC_SOFT_RESTART to the 32bit code
> - Add HVC_RESET_VECTORS to both arm and arm64, removing the need for
>   __hyp_reset_vectors
> - Implement add the stub entry points in the KVM init code, which
>   didn't implement any so far
> - Convert the HYP code to use the init code stubs directly
> - Some general cleanup as a result of these changes (which includes
>   killing HVC_GET_VECTORS)
> - Add some API documentation that covers the above
> 
> Patches 14 to 16 would be better squashed into 12 and 13, but I've
> kept them separate so that I can take the blame for everything I've
> broken.
> 
> I've tested this on arm (Cubietruck, Jetson TK1) and arm64 (Seattle),
> both as host and guest. Keerthy has been kind enough to test the 32bit
> code on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473472.html
> 
> * From v4:
>   - Added a standard return value on stub hypercall failure
>   - Zero r0/x0 on successful hypercall
>   - Make 32bit ARM resistant to kvm_reboot while executing a guest
>   - Update documentation to reflect the calling convention expectations
>   - Added Acks from Catalin
>   - Rebased on 4.11-rc5

Thanks for doing the changes.

I have applied your patches to kvmarm/queue.

-Christoffer