[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[PATCH v3 00/25] 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 9 to 11 would be better squashed into 7 and 8, but I've kept
separate so that I can take the blame for everything I've broken.

This has been tested on arm (Cubietruck, Jetson TK1) and arm64
(Seattle), both as host and guest.

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

* 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 (23):
  arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
  arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall
  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: Implement HVC_RESET_VECTORS stub hypercall
  ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall
  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/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
  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 | 45 ++++++++++++++++++++++++++++
 arch/arm/boot/compressed/head.S           |  5 +++-
 arch/arm/include/asm/kvm_asm.h            |  2 --
 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               | 12 +++++++-
 arch/arm/kernel/hyp-stub.S                | 39 +++++++++++++++++++-----
 arch/arm/kernel/reboot.c                  |  7 +++--
 arch/arm/kvm/arm.c                        | 25 ++++++----------
 arch/arm/kvm/hyp/hyp-entry.S              | 29 ++++++++++++++----
 arch/arm/kvm/init.S                       | 49 ++++++++++++++++++++++++++-----
 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          |  1 -
 arch/arm64/include/asm/kvm_host.h         |  7 -----
 arch/arm64/include/asm/kvm_mmu.h          |  1 -
 arch/arm64/include/asm/virt.h             | 17 +++++++----
 arch/arm64/kernel/hyp-stub.S              | 26 ++++++++--------
 arch/arm64/kvm/hyp-init.S                 | 45 +++++++++++++++++++++-------
 arch/arm64/kvm/hyp.S                      |  2 +-
 arch/arm64/kvm/hyp/hyp-entry.S            | 39 ++++++++++++------------
 24 files changed, 265 insertions(+), 126 deletions(-)
 create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt

-- 
2.11.0

[PATCH v3 00/25] 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 9 to 11 would be better squashed into 7 and 8, but I've kept
separate so that I can take the blame for everything I've broken.

This has been tested on arm (Cubietruck, Jetson TK1) and arm64
(Seattle), both as host and guest.

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

* 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 (23):
  arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
  arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall
  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: Implement HVC_RESET_VECTORS stub hypercall
  ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall
  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/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
  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 | 45 ++++++++++++++++++++++++++++
 arch/arm/boot/compressed/head.S           |  5 +++-
 arch/arm/include/asm/kvm_asm.h            |  2 --
 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               | 12 +++++++-
 arch/arm/kernel/hyp-stub.S                | 39 +++++++++++++++++++-----
 arch/arm/kernel/reboot.c                  |  7 +++--
 arch/arm/kvm/arm.c                        | 25 ++++++----------
 arch/arm/kvm/hyp/hyp-entry.S              | 29 ++++++++++++++----
 arch/arm/kvm/init.S                       | 49 ++++++++++++++++++++++++++-----
 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          |  1 -
 arch/arm64/include/asm/kvm_host.h         |  7 -----
 arch/arm64/include/asm/kvm_mmu.h          |  1 -
 arch/arm64/include/asm/virt.h             | 17 +++++++----
 arch/arm64/kernel/hyp-stub.S              | 26 ++++++++--------
 arch/arm64/kvm/hyp-init.S                 | 45 +++++++++++++++++++++-------
 arch/arm64/kvm/hyp.S                      |  2 +-
 arch/arm64/kvm/hyp/hyp-entry.S            | 39 ++++++++++++------------
 24 files changed, 265 insertions(+), 126 deletions(-)
 create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt

-- 
2.11.0

[PATCH v3 01/25] 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.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h |  9 +++++++++
 arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 439f6b5d31f6..f24f1eb72dc0 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -39,6 +39,14 @@
  */
 #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
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
@@ -62,6 +70,7 @@ 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 d3b5f75e652e..a162182d5662 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -79,8 +79,11 @@ 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:	mov	x0, #ARM_EXCEPTION_HYP_GONE
+	mov	x0, #ARM_EXCEPTION_HYP_GONE
 
 9:	eret
 ENDPROC(el1_sync)
@@ -137,3 +140,11 @@ ENTRY(__hyp_set_vectors)
 	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_set_vectors)
+
+ENTRY(__hyp_reset_vectors)
+	str	lr, [sp, #-16]!
+	mov	x0, #HVC_RESET_VECTORS
+	hvc	#0
+	ldr	lr, [sp], #16
+	ret
+ENDPROC(__hyp_reset_vectors)
-- 
2.11.0

[PATCH v3 01/25] 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.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h |  9 +++++++++
 arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 439f6b5d31f6..f24f1eb72dc0 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -39,6 +39,14 @@
  */
 #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
+
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
 
@@ -62,6 +70,7 @@ 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 d3b5f75e652e..a162182d5662 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -79,8 +79,11 @@ 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:	mov	x0, #ARM_EXCEPTION_HYP_GONE
+	mov	x0, #ARM_EXCEPTION_HYP_GONE
 
 9:	eret
 ENDPROC(el1_sync)
@@ -137,3 +140,11 @@ ENTRY(__hyp_set_vectors)
 	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_set_vectors)
+
+ENTRY(__hyp_reset_vectors)
+	str	lr, [sp, #-16]!
+	mov	x0, #HVC_RESET_VECTORS
+	hvc	#0
+	ldr	lr, [sp], #16
+	ret
+ENDPROC(__hyp_reset_vectors)
-- 
2.11.0

[PATCH v3 02/25] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall

[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.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 6b29d3d9e1f2..6cf98ccd10f2 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 +140,14 @@ ENTRY(__kvm_hyp_reset)
 	/* Install stub vectors */
 	adr_l	x0, __hyp_stub_vectors
 	msr	vbar_el2, x0
+	b	exit
 
+1:	mov	x0, #-1
+
+exit:
 	eret
 ENDPROC(__kvm_hyp_reset)
+ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
 
-- 
2.11.0

[PATCH v3 02/25] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall

[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.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/hyp-init.S | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 6b29d3d9e1f2..6cf98ccd10f2 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 +140,14 @@ ENTRY(__kvm_hyp_reset)
 	/* Install stub vectors */
 	adr_l	x0, __hyp_stub_vectors
 	msr	vbar_el2, x0
+	b	exit
 
+1:	mov	x0, #-1
+
+exit:
 	eret
 ENDPROC(__kvm_hyp_reset)
+ENDPROC(__kvm_handle_stub_hvc)
 
 	.ltorg
 
-- 
2.11.0

[PATCH v3 03/25] 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.

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 6cf98ccd10f2..1d89995378e9 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 v3 03/25] 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.

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 6cf98ccd10f2..1d89995378e9 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 v3 04/25] 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.

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 5e9052f087f2..21eeb2552f33 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 v3 04/25] 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.

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 5e9052f087f2..21eeb2552f33 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 v3 05/25] 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.

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 ec3553eb9349..3e242f6613b3 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 f21fd3894370..b8b6665dabbd 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -363,11 +363,10 @@ 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 1d89995378e9..b53e95efc1c5 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
@@ -151,7 +150,6 @@ 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 21eeb2552f33..1277f81b63b7 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 v3 05/25] 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.

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 ec3553eb9349..3e242f6613b3 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 f21fd3894370..b8b6665dabbd 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -363,11 +363,10 @@ 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 1d89995378e9..b53e95efc1c5 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
@@ -151,7 +150,6 @@ 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 21eeb2552f33..1277f81b63b7 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 v3 06/25] 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).

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 b53e95efc1c5..128d6e9732b9 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:	mov	x0, #-1
-- 
2.11.0

[PATCH v3 06/25] 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).

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 b53e95efc1c5..128d6e9732b9 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:	mov	x0, #-1
-- 
2.11.0

[PATCH v3 07/25] 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.

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 v3 07/25] 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.

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 v3 08/25] 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.

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 v3 08/25] 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.

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 v3 09/25] 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.

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 v3 09/25] 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.

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 v3 10/25] 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.

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 v3 10/25] 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.

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 v3 11/25] 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.

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 v3 11/25] 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.

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 v3 12/25] 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.

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 v3 12/25] 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.

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 v3 13/25] 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.

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 4ea16fcaf2ed..5186718aab68 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 15eaa14322a7..21794d4a8f36 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:	mov	r0, #-1
+1:	teq	r0, #HVC_RESET_VECTORS
+	beq	__hyp_stub_exit
+
+	mov	r0, #-1
 
 __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 v3 13/25] 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.

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 4ea16fcaf2ed..5186718aab68 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 15eaa14322a7..21794d4a8f36 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:	mov	r0, #-1
+1:	teq	r0, #HVC_RESET_VECTORS
+	beq	__hyp_stub_exit
+
+	mov	r0, #-1
 
 __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 v3 14/25] ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall

[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.

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 5186718aab68..8d5625b790b5 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 21794d4a8f36..3cb01e8a291d 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..9b0c735a68f7 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:	mov	r0, #-1
 
+exit:
 	eret
+ENDPROC(__kvm_handle_stub_hvc)
 ENDPROC(__kvm_hyp_reset)
 
 	.ltorg
-- 
2.11.0

[PATCH v3 14/25] ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall

[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.

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 5186718aab68..8d5625b790b5 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 21794d4a8f36..3cb01e8a291d 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..9b0c735a68f7 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:	mov	r0, #-1
 
+exit:
 	eret
+ENDPROC(__kvm_handle_stub_hvc)
 ENDPROC(__kvm_hyp_reset)
 
 	.ltorg
-- 
2.11.0

[PATCH v3 15/25] 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.

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 9b0c735a68f7..0da120b71c2e 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 v3 15/25] 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.

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 9b0c735a68f7..0da120b71c2e 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 v3 16/25] 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.

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 v3 16/25] 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.

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 v3 17/25] 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.

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 cc495d799c67..d75638beca4e 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -274,7 +274,7 @@ 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 0da120b71c2e..7335a510eee4 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 v3 17/25] 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.

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 cc495d799c67..d75638beca4e 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -274,7 +274,7 @@ 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 0da120b71c2e..7335a510eee4 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 v3 18/25] 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).

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 7335a510eee4..c92e092103b2 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 v3 18/25] 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).

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 7335a510eee4..c92e092103b2 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 v3 19/25] 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.

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 d75638beca4e..1590cd6849b0 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -271,12 +271,6 @@ 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 c9a2103faeb9..c07284044b1e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -1126,8 +1126,7 @@ 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 b8b6665dabbd..9a3d7b93944d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -363,12 +363,6 @@ 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 v3 19/25] 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.

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 d75638beca4e..1590cd6849b0 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -271,12 +271,6 @@ 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 c9a2103faeb9..c07284044b1e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -1126,8 +1126,7 @@ 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 b8b6665dabbd..9a3d7b93944d 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -363,12 +363,6 @@ 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 v3 20/25] 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.

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 v3 20/25] 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.

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 v3 21/25] 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.

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 c07284044b1e..2c192634a27d 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);
@@ -1109,8 +1108,16 @@ 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
@@ -1118,17 +1125,10 @@ 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)) {
@@ -1312,12 +1312,6 @@ 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 v3 21/25] 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.

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 c07284044b1e..2c192634a27d 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);
@@ -1109,8 +1108,16 @@ 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
@@ -1118,17 +1125,10 @@ 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)) {
@@ -1312,12 +1312,6 @@ 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 v3 22/25] 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.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/boot/compressed/head.S | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 9150f9732785..d58bb104c6e8 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -422,7 +422,10 @@ dtb_check_done:
 		cmp	r0, #HYP_MODE
 		bne	1f
 
-		bl	__hyp_get_vectors
+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 v3 22/25] 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.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/boot/compressed/head.S | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 9150f9732785..d58bb104c6e8 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -422,7 +422,10 @@ dtb_check_done:
 		cmp	r0, #HYP_MODE
 		bne	1f
 
-		bl	__hyp_get_vectors
+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 v3 23/25] 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).

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 8d5625b790b5..5f45969d4063 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 3cb01e8a291d..68bf72777ac7 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 c92e092103b2..3cff15152800 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 v3 23/25] 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).

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 8d5625b790b5..5f45969d4063 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 3cb01e8a291d..68bf72777ac7 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 c92e092103b2..3cff15152800 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 v3 24/25] 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).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h | 12 ++++--------
 arch/arm64/kernel/hyp-stub.S  | 15 +--------------
 arch/arm64/kvm/hyp-init.S     |  7 +------
 arch/arm64/kvm/hyp.S          |  2 +-
 4 files changed, 7 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index f24f1eb72dc0..a7c9dfdd6430 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -24,28 +24,25 @@
  * Any other value is used as a pointer to the function to call.
  */
 
-/* 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
 
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
@@ -69,7 +66,6 @@
 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 a162182d5662..8ccdd549f7c7 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -61,12 +61,7 @@ el1_sync:
 	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
-	b	9f
-
-1:	cmp	x0, #HVC_SET_VECTORS
+	cmp	x0, #HVC_SET_VECTORS
 	b.ne	2f
 	msr	vbar_el2, x1
 	b	9f
@@ -124,14 +119,6 @@ ENDPROC(\label)
  * initialisation entry point.
  */
 
-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
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 128d6e9732b9..cf01cdb8bc61 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 2726635dceba..09391cf0c93c 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.
  * HVC behaves as a 'bl' call and will clobber lr.
  */
-- 
2.11.0

[PATCH v3 24/25] 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).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/virt.h | 12 ++++--------
 arch/arm64/kernel/hyp-stub.S  | 15 +--------------
 arch/arm64/kvm/hyp-init.S     |  7 +------
 arch/arm64/kvm/hyp.S          |  2 +-
 4 files changed, 7 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index f24f1eb72dc0..a7c9dfdd6430 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -24,28 +24,25 @@
  * Any other value is used as a pointer to the function to call.
  */
 
-/* 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
 
 #define BOOT_CPU_MODE_EL1	(0xe11)
 #define BOOT_CPU_MODE_EL2	(0xe12)
@@ -69,7 +66,6 @@
 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 a162182d5662..8ccdd549f7c7 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -61,12 +61,7 @@ el1_sync:
 	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
-	b	9f
-
-1:	cmp	x0, #HVC_SET_VECTORS
+	cmp	x0, #HVC_SET_VECTORS
 	b.ne	2f
 	msr	vbar_el2, x1
 	b	9f
@@ -124,14 +119,6 @@ ENDPROC(\label)
  * initialisation entry point.
  */
 
-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
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 128d6e9732b9..cf01cdb8bc61 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 2726635dceba..09391cf0c93c 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.
  * HVC behaves as a 'bl' call and will clobber lr.
  */
-- 
2.11.0

[PATCH v3 25/25] 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 as with any form of documentation, I expect it to become obsolete
and completely misleading within 20 minutes after having being merged.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 Documentation/virtual/kvm/arm/hyp-abi.txt | 45 +++++++++++++++++++++++++++++++
 1 file changed, 45 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..a1e0314d2249
--- /dev/null
+++ b/Documentation/virtual/kvm/arm/hyp-abi.txt
@@ -0,0 +1,45 @@
+* 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.
+
+* r0/x0 = HVC_RESET_VECTORS
+
+  Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the default
+  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.
-- 
2.11.0

[PATCH v3 25/25] 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 as with any form of documentation, I expect it to become obsolete
and completely misleading within 20 minutes after having being merged.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 Documentation/virtual/kvm/arm/hyp-abi.txt | 45 +++++++++++++++++++++++++++++++
 1 file changed, 45 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..a1e0314d2249
--- /dev/null
+++ b/Documentation/virtual/kvm/arm/hyp-abi.txt
@@ -0,0 +1,45 @@
+* 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.
+
+* r0/x0 = HVC_RESET_VECTORS
+
+  Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the default
+  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.
-- 
2.11.0

Re: [PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

Re: [PATCH v3 02/25] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

(Nit: other patches to the init code in this series have 'init' in the subject,
this one doesn't.)

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

[PATCH v3 02/25] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

(Nit: other patches to the init code in this series have 'init' in the subject,
this one doesn't.)

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

Re: [PATCH v3 03/25] arm64: KVM: Implement HVC_GET_VECTORS in the init code

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> Now that we have an infrastructure to handle hypercalls in the KVM
> init code, let's implement HVC_GET_VECTORS there.

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

[PATCH v3 03/25] arm64: KVM: Implement HVC_GET_VECTORS in the init code

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> Now that we have an infrastructure to handle hypercalls in the KVM
> init code, let's implement HVC_GET_VECTORS there.

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

Re: [PATCH v3 04/25] arm64: KVM: Allow the main HYP code to use the init hyp stub implementation

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

Since your merged page tables change this isn't as scary as it looks, as the
idmap is always present.


Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

[PATCH v3 04/25] arm64: KVM: Allow the main HYP code to use the init hyp stub implementation

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

Since your merged page tables change this isn't as scary as it looks, as the
idmap is always present.


Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

Re: [PATCH v3 05/25] arm64: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

[PATCH v3 05/25] arm64: KVM: Convert __cpu_reset_hyp_mode to using __hyp_reset_vectors

[James Morse]

On 06/03/17 14:24, Marc Zyngier wrote:
> 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.

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

Re: [PATCH v3 02/25] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On Mon, Mar 13 2017 at  5:53:59 pm GMT, James Morse <james.morse@arm.com> wrote:
> On 06/03/17 14:24, Marc Zyngier wrote:
>> 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.
>
> (Nit: other patches to the init code in this series have 'init' in the subject,
> this one doesn't.)

Good point, I'll update the series locally to reflect this.

> Reviewed-by: James Morse <james.morse@arm.com>

Thanks!

	M.
-- 
Jazz is not dead, it just smell funny.

Re: [PATCH v3 02/25] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On Mon, Mar 13 2017 at  5:53:59 pm GMT, James Morse <james.morse@arm.com> wrote:
> On 06/03/17 14:24, Marc Zyngier wrote:
>> 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.
>
> (Nit: other patches to the init code in this series have 'init' in the subject,
> this one doesn't.)

Good point, I'll update the series locally to reflect this.

> Reviewed-by: James Morse <james.morse@arm.com>

Thanks!

	M.
-- 
Jazz is not dead, it just smell funny.

[PATCH v3 02/25] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On Mon, Mar 13 2017 at  5:53:59 pm GMT, James Morse <james.morse@arm.com> wrote:
> On 06/03/17 14:24, Marc Zyngier wrote:
>> 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.
>
> (Nit: other patches to the init code in this series have 'init' in the subject,
> this one doesn't.)

Good point, I'll update the series locally to reflect this.

> Reviewed-by: James Morse <james.morse@arm.com>

Thanks!

	M.
-- 
Jazz is not dead, it just smell funny.

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Keerthy]

On Monday 06 March 2017 07:54 PM, 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 9 to 11 would be better squashed into 7 and 8, but I've kept
> separate so that I can take the blame for everything I've broken.

Tested for kexec booting with the patch series applied on linux-next.

kexec is working nicely with HYP and SVC modes. Tested for both modes by
using different u-boot for booting in HYP and SVC modes. Kexec works well.

Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.

Tested-by: Keerthy <j-keerthy@ti.com>

> 
> This has been tested on arm (Cubietruck, Jetson TK1) and arm64
> (Seattle), both as host and guest.
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473472.html
> 
> * 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 (23):
>   arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
>   arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall
>   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: Implement HVC_RESET_VECTORS stub hypercall
>   ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall
>   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/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
>   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 | 45 ++++++++++++++++++++++++++++
>  arch/arm/boot/compressed/head.S           |  5 +++-
>  arch/arm/include/asm/kvm_asm.h            |  2 --
>  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               | 12 +++++++-
>  arch/arm/kernel/hyp-stub.S                | 39 +++++++++++++++++++-----
>  arch/arm/kernel/reboot.c                  |  7 +++--
>  arch/arm/kvm/arm.c                        | 25 ++++++----------
>  arch/arm/kvm/hyp/hyp-entry.S              | 29 ++++++++++++++----
>  arch/arm/kvm/init.S                       | 49 ++++++++++++++++++++++++++-----
>  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          |  1 -
>  arch/arm64/include/asm/kvm_host.h         |  7 -----
>  arch/arm64/include/asm/kvm_mmu.h          |  1 -
>  arch/arm64/include/asm/virt.h             | 17 +++++++----
>  arch/arm64/kernel/hyp-stub.S              | 26 ++++++++--------
>  arch/arm64/kvm/hyp-init.S                 | 45 +++++++++++++++++++++-------
>  arch/arm64/kvm/hyp.S                      |  2 +-
>  arch/arm64/kvm/hyp/hyp-entry.S            | 39 ++++++++++++------------
>  24 files changed, 265 insertions(+), 126 deletions(-)
>  create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt
> 

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Keerthy]

On Monday 06 March 2017 07:54 PM, 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 9 to 11 would be better squashed into 7 and 8, but I've kept
> separate so that I can take the blame for everything I've broken.

Tested for kexec booting with the patch series applied on linux-next.

kexec is working nicely with HYP and SVC modes. Tested for both modes by
using different u-boot for booting in HYP and SVC modes. Kexec works well.

Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.

Tested-by: Keerthy <j-keerthy@ti.com>

> 
> This has been tested on arm (Cubietruck, Jetson TK1) and arm64
> (Seattle), both as host and guest.
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473472.html
> 
> * 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 (23):
>   arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
>   arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall
>   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: Implement HVC_RESET_VECTORS stub hypercall
>   ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall
>   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/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
>   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 | 45 ++++++++++++++++++++++++++++
>  arch/arm/boot/compressed/head.S           |  5 +++-
>  arch/arm/include/asm/kvm_asm.h            |  2 --
>  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               | 12 +++++++-
>  arch/arm/kernel/hyp-stub.S                | 39 +++++++++++++++++++-----
>  arch/arm/kernel/reboot.c                  |  7 +++--
>  arch/arm/kvm/arm.c                        | 25 ++++++----------
>  arch/arm/kvm/hyp/hyp-entry.S              | 29 ++++++++++++++----
>  arch/arm/kvm/init.S                       | 49 ++++++++++++++++++++++++++-----
>  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          |  1 -
>  arch/arm64/include/asm/kvm_host.h         |  7 -----
>  arch/arm64/include/asm/kvm_mmu.h          |  1 -
>  arch/arm64/include/asm/virt.h             | 17 +++++++----
>  arch/arm64/kernel/hyp-stub.S              | 26 ++++++++--------
>  arch/arm64/kvm/hyp-init.S                 | 45 +++++++++++++++++++++-------
>  arch/arm64/kvm/hyp.S                      |  2 +-
>  arch/arm64/kvm/hyp/hyp-entry.S            | 39 ++++++++++++------------
>  24 files changed, 265 insertions(+), 126 deletions(-)
>  create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt
> 

[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Keerthy]

On Monday 06 March 2017 07:54 PM, 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 9 to 11 would be better squashed into 7 and 8, but I've kept
> separate so that I can take the blame for everything I've broken.

Tested for kexec booting with the patch series applied on linux-next.

kexec is working nicely with HYP and SVC modes. Tested for both modes by
using different u-boot for booting in HYP and SVC modes. Kexec works well.

Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.

Tested-by: Keerthy <j-keerthy@ti.com>

> 
> This has been tested on arm (Cubietruck, Jetson TK1) and arm64
> (Seattle), both as host and guest.
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473472.html
> 
> * 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 (23):
>   arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall
>   arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall
>   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: Implement HVC_RESET_VECTORS stub hypercall
>   ARM: KVM: Implement HVC_RESET_VECTORS stub hypercall
>   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/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
>   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 | 45 ++++++++++++++++++++++++++++
>  arch/arm/boot/compressed/head.S           |  5 +++-
>  arch/arm/include/asm/kvm_asm.h            |  2 --
>  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               | 12 +++++++-
>  arch/arm/kernel/hyp-stub.S                | 39 +++++++++++++++++++-----
>  arch/arm/kernel/reboot.c                  |  7 +++--
>  arch/arm/kvm/arm.c                        | 25 ++++++----------
>  arch/arm/kvm/hyp/hyp-entry.S              | 29 ++++++++++++++----
>  arch/arm/kvm/init.S                       | 49 ++++++++++++++++++++++++++-----
>  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          |  1 -
>  arch/arm64/include/asm/kvm_host.h         |  7 -----
>  arch/arm64/include/asm/kvm_mmu.h          |  1 -
>  arch/arm64/include/asm/virt.h             | 17 +++++++----
>  arch/arm64/kernel/hyp-stub.S              | 26 ++++++++--------
>  arch/arm64/kvm/hyp-init.S                 | 45 +++++++++++++++++++++-------
>  arch/arm64/kvm/hyp.S                      |  2 +-
>  arch/arm64/kvm/hyp/hyp-entry.S            | 39 ++++++++++++------------
>  24 files changed, 265 insertions(+), 126 deletions(-)
>  create mode 100644 Documentation/virtual/kvm/arm/hyp-abi.txt
> 

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Marc Zyngier]

On 14/03/17 13:38, Keerthy wrote:
> 
> 
> On Monday 06 March 2017 07:54 PM, 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 9 to 11 would be better squashed into 7 and 8, but I've kept
>> separate so that I can take the blame for everything I've broken.
> 
> Tested for kexec booting with the patch series applied on linux-next.
> 
> kexec is working nicely with HYP and SVC modes. Tested for both modes by
> using different u-boot for booting in HYP and SVC modes. Kexec works well.
> 
> Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
> 
> Tested-by: Keerthy <j-keerthy@ti.com>

Thanks a lot. I assume this Tested-by applies to the 32bit patches in
this series?

Cheers,

	M.
-- 
Jazz is not dead. It just smells funny...

[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Marc Zyngier]

On 14/03/17 13:38, Keerthy wrote:
> 
> 
> On Monday 06 March 2017 07:54 PM, 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 9 to 11 would be better squashed into 7 and 8, but I've kept
>> separate so that I can take the blame for everything I've broken.
> 
> Tested for kexec booting with the patch series applied on linux-next.
> 
> kexec is working nicely with HYP and SVC modes. Tested for both modes by
> using different u-boot for booting in HYP and SVC modes. Kexec works well.
> 
> Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
> 
> Tested-by: Keerthy <j-keerthy@ti.com>

Thanks a lot. I assume this Tested-by applies to the 32bit patches in
this series?

Cheers,

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Nishanth Menon]

On Tue, Mar 14, 2017 at 8:55 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
[...]
>> Tested for kexec booting with the patch series applied on linux-next.
>>
>> kexec is working nicely with HYP and SVC modes. Tested for both modes by
>> using different u-boot for booting in HYP and SVC modes. Kexec works well.
>>
>> Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
>>
>> Tested-by: Keerthy <j-keerthy@ti.com>
>
> Thanks a lot. I assume this Tested-by applies to the 32bit patches in
> this series?

Yes, the above platform list from Keerthy are all A15 32bit platforms.

---
Regards,
Nishanth Menon

[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Nishanth Menon]

On Tue, Mar 14, 2017 at 8:55 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
[...]
>> Tested for kexec booting with the patch series applied on linux-next.
>>
>> kexec is working nicely with HYP and SVC modes. Tested for both modes by
>> using different u-boot for booting in HYP and SVC modes. Kexec works well.
>>
>> Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
>>
>> Tested-by: Keerthy <j-keerthy@ti.com>
>
> Thanks a lot. I assume this Tested-by applies to the 32bit patches in
> this series?

Yes, the above platform list from Keerthy are all A15 32bit platforms.

---
Regards,
Nishanth Menon

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Russell King - ARM Linux]

On Mon, Mar 06, 2017 at 02:24:33PM +0000, 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.

What's the merge plan for this?

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Russell King - ARM Linux]

On Mon, Mar 06, 2017 at 02:24:33PM +0000, 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.

What's the merge plan for this?

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Marc Zyngier]

On 14/03/17 16:05, Russell King - ARM Linux wrote:
> On Mon, Mar 06, 2017 at 02:24:33PM +0000, 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.
> 
> What's the merge plan for this?

If you're happy with it (together with Christoffer, Will and Catalin), I
plat to take it through the kvmarm tree.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Marc Zyngier]

On 14/03/17 16:05, Russell King - ARM Linux wrote:
> On Mon, Mar 06, 2017 at 02:24:33PM +0000, 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.
> 
> What's the merge plan for this?

If you're happy with it (together with Christoffer, Will and Catalin), I
plat to take it through the kvmarm tree.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Keerthy]

On Tuesday 14 March 2017 07:55 PM, Nishanth Menon wrote:
> On Tue, Mar 14, 2017 at 8:55 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> [...]
>>> Tested for kexec booting with the patch series applied on linux-next.
>>>
>>> kexec is working nicely with HYP and SVC modes. Tested for both modes by
>>> using different u-boot for booting in HYP and SVC modes. Kexec works well.
>>>
>>> Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
>>>
>>> Tested-by: Keerthy <j-keerthy@ti.com>
>>
>> Thanks a lot. I assume this Tested-by applies to the 32bit patches in
>> this series?
> 
> Yes, the above platform list from Keerthy are all A15 32bit platforms.

Yes Marc. All are 32 bit platforms.

> 
> ---
> Regards,
> Nishanth Menon
> 

[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Keerthy]

On Tuesday 14 March 2017 07:55 PM, Nishanth Menon wrote:
> On Tue, Mar 14, 2017 at 8:55 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> [...]
>>> Tested for kexec booting with the patch series applied on linux-next.
>>>
>>> kexec is working nicely with HYP and SVC modes. Tested for both modes by
>>> using different u-boot for booting in HYP and SVC modes. Kexec works well.
>>>
>>> Tested on DRA7-EVM, AM57XX-EVM and KEYSTONE-K2E-EVM.
>>>
>>> Tested-by: Keerthy <j-keerthy@ti.com>
>>
>> Thanks a lot. I assume this Tested-by applies to the 32bit patches in
>> this series?
> 
> Yes, the above platform list from Keerthy are all A15 32bit platforms.

Yes Marc. All are 32 bit platforms.

> 
> ---
> Regards,
> Nishanth Menon
> 

Re: [PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Russell King - ARM Linux]

On Tue, Mar 14, 2017 at 04:09:44PM +0000, Marc Zyngier wrote:
> On 14/03/17 16:05, Russell King - ARM Linux wrote:
> > On Mon, Mar 06, 2017 at 02:24:33PM +0000, 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.
> > 
> > What's the merge plan for this?
> 
> If you're happy with it (together with Christoffer, Will and Catalin), I
> plat to take it through the kvmarm tree.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>

Thanks.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

[PATCH v3 00/25] arm/arm64: KVM: Rework the hyp-stub API

[Russell King - ARM Linux]

On Tue, Mar 14, 2017 at 04:09:44PM +0000, Marc Zyngier wrote:
> On 14/03/17 16:05, Russell King - ARM Linux wrote:
> > On Mon, Mar 06, 2017 at 02:24:33PM +0000, 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.
> > 
> > What's the merge plan for this?
> 
> If you're happy with it (together with Christoffer, Will and Catalin), I
> plat to take it through the kvmarm tree.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>

Thanks.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Catalin Marinas]

On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
> 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.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/include/asm/virt.h |  9 +++++++++
>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>  2 files changed, 21 insertions(+), 1 deletion(-)
[...]
> +ENTRY(__hyp_reset_vectors)
> +	str	lr, [sp, #-16]!
> +	mov	x0, #HVC_RESET_VECTORS
> +	hvc	#0
> +	ldr	lr, [sp], #16
> +	ret
> +ENDPROC(__hyp_reset_vectors)

Why do we need to specifically preserve lr across the hvc call? Is it
corrupted by the EL2 code (if yes, are other caller-saved registers that
need preserving)? I don't see something similar in the arch/arm code.

-- 
Catalin

[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Catalin Marinas]

On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
> 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.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/include/asm/virt.h |  9 +++++++++
>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>  2 files changed, 21 insertions(+), 1 deletion(-)
[...]
> +ENTRY(__hyp_reset_vectors)
> +	str	lr, [sp, #-16]!
> +	mov	x0, #HVC_RESET_VECTORS
> +	hvc	#0
> +	ldr	lr, [sp], #16
> +	ret
> +ENDPROC(__hyp_reset_vectors)

Why do we need to specifically preserve lr across the hvc call? Is it
corrupted by the EL2 code (if yes, are other caller-saved registers that
need preserving)? I don't see something similar in the arch/arm code.

-- 
Catalin

Re: [PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

Hi Catalin,

On 21/03/17 17:04, Catalin Marinas wrote:
> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>> 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.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>  2 files changed, 21 insertions(+), 1 deletion(-)
> [...]
>> +ENTRY(__hyp_reset_vectors)
>> +	str	lr, [sp, #-16]!
>> +	mov	x0, #HVC_RESET_VECTORS
>> +	hvc	#0
>> +	ldr	lr, [sp], #16
>> +	ret
>> +ENDPROC(__hyp_reset_vectors)
> 
> Why do we need to specifically preserve lr across the hvc call? Is it
> corrupted by the EL2 code (if yes, are other caller-saved registers that
> need preserving)? I don't see something similar in the arch/arm code.

Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
wanted to preserve all the registers so soft_restart() could look more like a
function call.


Thanks,

James

[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

Hi Catalin,

On 21/03/17 17:04, Catalin Marinas wrote:
> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>> 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.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>  2 files changed, 21 insertions(+), 1 deletion(-)
> [...]
>> +ENTRY(__hyp_reset_vectors)
>> +	str	lr, [sp, #-16]!
>> +	mov	x0, #HVC_RESET_VECTORS
>> +	hvc	#0
>> +	ldr	lr, [sp], #16
>> +	ret
>> +ENDPROC(__hyp_reset_vectors)
> 
> Why do we need to specifically preserve lr across the hvc call? Is it
> corrupted by the EL2 code (if yes, are other caller-saved registers that
> need preserving)? I don't see something similar in the arch/arm code.

Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
wanted to preserve all the registers so soft_restart() could look more like a
function call.


Thanks,

James

Re: [PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On 21/03/17 17:04, Catalin Marinas wrote:
> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>> 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.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>  2 files changed, 21 insertions(+), 1 deletion(-)
> [...]
>> +ENTRY(__hyp_reset_vectors)
>> +	str	lr, [sp, #-16]!
>> +	mov	x0, #HVC_RESET_VECTORS
>> +	hvc	#0
>> +	ldr	lr, [sp], #16
>> +	ret
>> +ENDPROC(__hyp_reset_vectors)
> 
> Why do we need to specifically preserve lr across the hvc call? Is it
> corrupted by the EL2 code (if yes, are other caller-saved registers that
> need preserving)? I don't see something similar in the arch/arm code.

Yeah, that's another oddity. The KVM code uses it as a temp register,
but that feels quite wrong, now that you mention it. If should be saved
there, and definitely not in the stubs.

Let me grab a hammer, and I'll set that one straight.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On 21/03/17 17:04, Catalin Marinas wrote:
> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>> 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.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>  2 files changed, 21 insertions(+), 1 deletion(-)
> [...]
>> +ENTRY(__hyp_reset_vectors)
>> +	str	lr, [sp, #-16]!
>> +	mov	x0, #HVC_RESET_VECTORS
>> +	hvc	#0
>> +	ldr	lr, [sp], #16
>> +	ret
>> +ENDPROC(__hyp_reset_vectors)
> 
> Why do we need to specifically preserve lr across the hvc call? Is it
> corrupted by the EL2 code (if yes, are other caller-saved registers that
> need preserving)? I don't see something similar in the arch/arm code.

Yeah, that's another oddity. The KVM code uses it as a temp register,
but that feels quite wrong, now that you mention it. If should be saved
there, and definitely not in the stubs.

Let me grab a hammer, and I'll set that one straight.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On 21/03/17 17:25, James Morse wrote:
> Hi Catalin,
> 
> On 21/03/17 17:04, Catalin Marinas wrote:
>> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>>> 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.
>>>
>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>> ---
>>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>>  2 files changed, 21 insertions(+), 1 deletion(-)
>> [...]
>>> +ENTRY(__hyp_reset_vectors)
>>> +	str	lr, [sp, #-16]!
>>> +	mov	x0, #HVC_RESET_VECTORS
>>> +	hvc	#0
>>> +	ldr	lr, [sp], #16
>>> +	ret
>>> +ENDPROC(__hyp_reset_vectors)
>>
>> Why do we need to specifically preserve lr across the hvc call? Is it
>> corrupted by the EL2 code (if yes, are other caller-saved registers that
>> need preserving)? I don't see something similar in the arch/arm code.
> 
> Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
> wanted to preserve all the registers so soft_restart() could look more like a
> function call.

I don't think we need this anymore. Once we enter __cpu_soft_restart(),
there is no turning back. Or am I missing something else?

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On 21/03/17 17:25, James Morse wrote:
> Hi Catalin,
> 
> On 21/03/17 17:04, Catalin Marinas wrote:
>> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>>> 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.
>>>
>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>> ---
>>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>>  2 files changed, 21 insertions(+), 1 deletion(-)
>> [...]
>>> +ENTRY(__hyp_reset_vectors)
>>> +	str	lr, [sp, #-16]!
>>> +	mov	x0, #HVC_RESET_VECTORS
>>> +	hvc	#0
>>> +	ldr	lr, [sp], #16
>>> +	ret
>>> +ENDPROC(__hyp_reset_vectors)
>>
>> Why do we need to specifically preserve lr across the hvc call? Is it
>> corrupted by the EL2 code (if yes, are other caller-saved registers that
>> need preserving)? I don't see something similar in the arch/arm code.
> 
> Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
> wanted to preserve all the registers so soft_restart() could look more like a
> function call.

I don't think we need this anymore. Once we enter __cpu_soft_restart(),
there is no turning back. Or am I missing something else?

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

On 21/03/17 17:37, Marc Zyngier wrote:
> On 21/03/17 17:25, James Morse wrote:
>> On 21/03/17 17:04, Catalin Marinas wrote:
>>> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>>>> 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.
>>>>
>>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>>> ---
>>>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>>>  2 files changed, 21 insertions(+), 1 deletion(-)
>>> [...]
>>>> +ENTRY(__hyp_reset_vectors)
>>>> +	str	lr, [sp, #-16]!
>>>> +	mov	x0, #HVC_RESET_VECTORS
>>>> +	hvc	#0
>>>> +	ldr	lr, [sp], #16
>>>> +	ret
>>>> +ENDPROC(__hyp_reset_vectors)
>>>
>>> Why do we need to specifically preserve lr across the hvc call? Is it
>>> corrupted by the EL2 code (if yes, are other caller-saved registers that
>>> need preserving)? I don't see something similar in the arch/arm code.
>>
>> Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
>> wanted to preserve all the registers so soft_restart() could look more like a
>> function call.
> 
> I don't think we need this anymore. Once we enter __cpu_soft_restart(),
> there is no turning back. Or am I missing something else?

My recollection of the history may be wrong: but we needed to mess with esr_el2
before we know its a soft_restart() call, at which point we didn't want to
clobber the registers. This was the strange use of x18 in kexec.


James

[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[James Morse]

On 21/03/17 17:37, Marc Zyngier wrote:
> On 21/03/17 17:25, James Morse wrote:
>> On 21/03/17 17:04, Catalin Marinas wrote:
>>> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>>>> 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.
>>>>
>>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>>> ---
>>>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>>>  2 files changed, 21 insertions(+), 1 deletion(-)
>>> [...]
>>>> +ENTRY(__hyp_reset_vectors)
>>>> +	str	lr, [sp, #-16]!
>>>> +	mov	x0, #HVC_RESET_VECTORS
>>>> +	hvc	#0
>>>> +	ldr	lr, [sp], #16
>>>> +	ret
>>>> +ENDPROC(__hyp_reset_vectors)
>>>
>>> Why do we need to specifically preserve lr across the hvc call? Is it
>>> corrupted by the EL2 code (if yes, are other caller-saved registers that
>>> need preserving)? I don't see something similar in the arch/arm code.
>>
>> Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
>> wanted to preserve all the registers so soft_restart() could look more like a
>> function call.
> 
> I don't think we need this anymore. Once we enter __cpu_soft_restart(),
> there is no turning back. Or am I missing something else?

My recollection of the history may be wrong: but we needed to mess with esr_el2
before we know its a soft_restart() call, at which point we didn't want to
clobber the registers. This was the strange use of x18 in kexec.


James

Re: [PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On 21/03/17 17:41, James Morse wrote:
> On 21/03/17 17:37, Marc Zyngier wrote:
>> On 21/03/17 17:25, James Morse wrote:
>>> On 21/03/17 17:04, Catalin Marinas wrote:
>>>> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>>>>> 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.
>>>>>
>>>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>>>> ---
>>>>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>>>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>>>>  2 files changed, 21 insertions(+), 1 deletion(-)
>>>> [...]
>>>>> +ENTRY(__hyp_reset_vectors)
>>>>> +	str	lr, [sp, #-16]!
>>>>> +	mov	x0, #HVC_RESET_VECTORS
>>>>> +	hvc	#0
>>>>> +	ldr	lr, [sp], #16
>>>>> +	ret
>>>>> +ENDPROC(__hyp_reset_vectors)
>>>>
>>>> Why do we need to specifically preserve lr across the hvc call? Is it
>>>> corrupted by the EL2 code (if yes, are other caller-saved registers that
>>>> need preserving)? I don't see something similar in the arch/arm code.
>>>
>>> Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
>>> wanted to preserve all the registers so soft_restart() could look more like a
>>> function call.
>>
>> I don't think we need this anymore. Once we enter __cpu_soft_restart(),
>> there is no turning back. Or am I missing something else?
> 
> My recollection of the history may be wrong: but we needed to mess with esr_el2
> before we know its a soft_restart() call, at which point we didn't want to
> clobber the registers. This was the strange use of x18 in kexec.

After a bit of digging together with James, we found the guilty one.
The hyp-stub entry code uses lr (aka x30) as a scratch register to 
find out if we've made it here via a HVC instruction. This is an 
absolutely pointless test, because by definition HVC is the only way to 
get there.

I've ended up with the following patch:

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 8ccdd549f7c7..210bd6b3849d 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_SET_VECTORS
 	b.ne	2f
 	msr	vbar_el2, x1
@@ -120,18 +114,14 @@ ENDPROC(\label)
  */
 
 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)
 
 ENTRY(__hyp_reset_vectors)
-	str	lr, [sp, #-16]!
 	mov	x0, #HVC_RESET_VECTORS
 	hvc	#0
-	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_reset_vectors)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 1277f81b63b7..5170ce1021da 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.

I'll split that in convenient patches and repost the series.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

[PATCH v3 01/25] arm64: hyp-stub: Implement HVC_RESET_VECTORS stub hypercall

[Marc Zyngier]

On 21/03/17 17:41, James Morse wrote:
> On 21/03/17 17:37, Marc Zyngier wrote:
>> On 21/03/17 17:25, James Morse wrote:
>>> On 21/03/17 17:04, Catalin Marinas wrote:
>>>> On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote:
>>>>> 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.
>>>>>
>>>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>>>> ---
>>>>>  arch/arm64/include/asm/virt.h |  9 +++++++++
>>>>>  arch/arm64/kernel/hyp-stub.S  | 13 ++++++++++++-
>>>>>  2 files changed, 21 insertions(+), 1 deletion(-)
>>>> [...]
>>>>> +ENTRY(__hyp_reset_vectors)
>>>>> +	str	lr, [sp, #-16]!
>>>>> +	mov	x0, #HVC_RESET_VECTORS
>>>>> +	hvc	#0
>>>>> +	ldr	lr, [sp], #16
>>>>> +	ret
>>>>> +ENDPROC(__hyp_reset_vectors)
>>>>
>>>> Why do we need to specifically preserve lr across the hvc call? Is it
>>>> corrupted by the EL2 code (if yes, are other caller-saved registers that
>>>> need preserving)? I don't see something similar in the arch/arm code.
>>>
>>> Kexec on arm64 needed a register to clobber in the hyp-stub's el1_sync code. We
>>> wanted to preserve all the registers so soft_restart() could look more like a
>>> function call.
>>
>> I don't think we need this anymore. Once we enter __cpu_soft_restart(),
>> there is no turning back. Or am I missing something else?
> 
> My recollection of the history may be wrong: but we needed to mess with esr_el2
> before we know its a soft_restart() call, at which point we didn't want to
> clobber the registers. This was the strange use of x18 in kexec.

After a bit of digging together with James, we found the guilty one.
The hyp-stub entry code uses lr (aka x30) as a scratch register to 
find out if we've made it here via a HVC instruction. This is an 
absolutely pointless test, because by definition HVC is the only way to 
get there.

I've ended up with the following patch:

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 8ccdd549f7c7..210bd6b3849d 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_SET_VECTORS
 	b.ne	2f
 	msr	vbar_el2, x1
@@ -120,18 +114,14 @@ ENDPROC(\label)
  */
 
 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)
 
 ENTRY(__hyp_reset_vectors)
-	str	lr, [sp, #-16]!
 	mov	x0, #HVC_RESET_VECTORS
 	hvc	#0
-	ldr	lr, [sp], #16
 	ret
 ENDPROC(__hyp_reset_vectors)
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 1277f81b63b7..5170ce1021da 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.

I'll split that in convenient patches and repost the series.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...