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* [PATCH] KVM: arm64: Fix nVHE hyp panic host context restore
@ 2021-03-15 12:21 ` Andrew Scull
  0 siblings, 0 replies; 5+ messages in thread
From: Andrew Scull @ 2021-03-15 12:21 UTC (permalink / raw)
  To: kvmarm; +Cc: maz, kernel-team, Andrew Scull, stable

Commit c4b000c3928d4f20acef79dccf3a65ae3795e0b0 upstream.

When panicking from the nVHE hyp and restoring the host context, x29 is
expected to hold a pointer to the host context. This wasn't being done
so fix it to make sure there's a valid pointer the host context being
used.

Rather than passing a boolean indicating whether or not the host context
should be restored, instead pass the pointer to the host context. NULL
is passed to indicate that no context should be restored.

Fixes: a2e102e20fd6 ("KVM: arm64: nVHE: Handle hyp panics")
Cc: stable@vger.kernel.org # 5.11.y only
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@google.com
---
 arch/arm64/include/asm/kvm_hyp.h |  3 ++-
 arch/arm64/kvm/hyp/nvhe/host.S   | 20 ++++++++++----------
 arch/arm64/kvm/hyp/nvhe/switch.c |  3 +--
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index c0450828378b..fb8404fefd1f 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -97,7 +97,8 @@ bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt);
 
 void __noreturn hyp_panic(void);
 #ifdef __KVM_NVHE_HYPERVISOR__
-void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
+void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
+			       u64 elr, u64 par);
 #endif
 
 #endif /* __ARM64_KVM_HYP_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index a820dfdc9c25..3a06085aab6f 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -71,10 +71,15 @@ SYM_FUNC_START(__host_enter)
 SYM_FUNC_END(__host_enter)
 
 /*
- * void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
+ * void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
+ * 				  u64 elr, u64 par);
  */
 SYM_FUNC_START(__hyp_do_panic)
-	/* Load the format arguments into x1-7 */
+	mov	x29, x0
+
+	/* Load the format string into x0 and arguments into x1-7 */
+	ldr	x0, =__hyp_panic_string
+
 	mov	x6, x3
 	get_vcpu_ptr x7, x3
 
@@ -89,13 +94,8 @@ SYM_FUNC_START(__hyp_do_panic)
 	ldr	lr, =panic
 	msr	elr_el2, lr
 
-	/*
-	 * Set the panic format string and enter the host, conditionally
-	 * restoring the host context.
-	 */
-	cmp	x0, xzr
-	ldr	x0, =__hyp_panic_string
-	b.eq	__host_enter_without_restoring
+	/* Enter the host, conditionally restoring the host context. */
+	cbz	x29, __host_enter_without_restoring
 	b	__host_enter_for_panic
 SYM_FUNC_END(__hyp_do_panic)
 
@@ -150,7 +150,7 @@ SYM_FUNC_END(__hyp_do_panic)
 
 .macro invalid_host_el1_vect
 	.align 7
-	mov	x0, xzr		/* restore_host = false */
+	mov	x0, xzr		/* host_ctxt = NULL */
 	mrs	x1, spsr_el2
 	mrs	x2, elr_el2
 	mrs	x3, par_el1
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index f3d0e9eca56c..038147b7674b 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -257,7 +257,6 @@ void __noreturn hyp_panic(void)
 	u64 spsr = read_sysreg_el2(SYS_SPSR);
 	u64 elr = read_sysreg_el2(SYS_ELR);
 	u64 par = read_sysreg_par();
-	bool restore_host = true;
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_vcpu *vcpu;
 
@@ -271,7 +270,7 @@ void __noreturn hyp_panic(void)
 		__sysreg_restore_state_nvhe(host_ctxt);
 	}
 
-	__hyp_do_panic(restore_host, spsr, elr, par);
+	__hyp_do_panic(host_ctxt, spsr, elr, par);
 	unreachable();
 }
 
-- 
2.31.0.rc2.261.g7f71774620-goog


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* [PATCH] KVM: arm64: Fix nVHE hyp panic host context restore
@ 2021-03-15 12:21 ` Andrew Scull
  0 siblings, 0 replies; 5+ messages in thread
From: Andrew Scull @ 2021-03-15 12:21 UTC (permalink / raw)
  To: kvmarm; +Cc: maz, kernel-team, stable

Commit c4b000c3928d4f20acef79dccf3a65ae3795e0b0 upstream.

When panicking from the nVHE hyp and restoring the host context, x29 is
expected to hold a pointer to the host context. This wasn't being done
so fix it to make sure there's a valid pointer the host context being
used.

Rather than passing a boolean indicating whether or not the host context
should be restored, instead pass the pointer to the host context. NULL
is passed to indicate that no context should be restored.

Fixes: a2e102e20fd6 ("KVM: arm64: nVHE: Handle hyp panics")
Cc: stable@vger.kernel.org # 5.11.y only
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@google.com
---
 arch/arm64/include/asm/kvm_hyp.h |  3 ++-
 arch/arm64/kvm/hyp/nvhe/host.S   | 20 ++++++++++----------
 arch/arm64/kvm/hyp/nvhe/switch.c |  3 +--
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index c0450828378b..fb8404fefd1f 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -97,7 +97,8 @@ bool kvm_host_psci_handler(struct kvm_cpu_context *host_ctxt);
 
 void __noreturn hyp_panic(void);
 #ifdef __KVM_NVHE_HYPERVISOR__
-void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
+void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
+			       u64 elr, u64 par);
 #endif
 
 #endif /* __ARM64_KVM_HYP_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index a820dfdc9c25..3a06085aab6f 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -71,10 +71,15 @@ SYM_FUNC_START(__host_enter)
 SYM_FUNC_END(__host_enter)
 
 /*
- * void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
+ * void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
+ * 				  u64 elr, u64 par);
  */
 SYM_FUNC_START(__hyp_do_panic)
-	/* Load the format arguments into x1-7 */
+	mov	x29, x0
+
+	/* Load the format string into x0 and arguments into x1-7 */
+	ldr	x0, =__hyp_panic_string
+
 	mov	x6, x3
 	get_vcpu_ptr x7, x3
 
@@ -89,13 +94,8 @@ SYM_FUNC_START(__hyp_do_panic)
 	ldr	lr, =panic
 	msr	elr_el2, lr
 
-	/*
-	 * Set the panic format string and enter the host, conditionally
-	 * restoring the host context.
-	 */
-	cmp	x0, xzr
-	ldr	x0, =__hyp_panic_string
-	b.eq	__host_enter_without_restoring
+	/* Enter the host, conditionally restoring the host context. */
+	cbz	x29, __host_enter_without_restoring
 	b	__host_enter_for_panic
 SYM_FUNC_END(__hyp_do_panic)
 
@@ -150,7 +150,7 @@ SYM_FUNC_END(__hyp_do_panic)
 
 .macro invalid_host_el1_vect
 	.align 7
-	mov	x0, xzr		/* restore_host = false */
+	mov	x0, xzr		/* host_ctxt = NULL */
 	mrs	x1, spsr_el2
 	mrs	x2, elr_el2
 	mrs	x3, par_el1
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index f3d0e9eca56c..038147b7674b 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -257,7 +257,6 @@ void __noreturn hyp_panic(void)
 	u64 spsr = read_sysreg_el2(SYS_SPSR);
 	u64 elr = read_sysreg_el2(SYS_ELR);
 	u64 par = read_sysreg_par();
-	bool restore_host = true;
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_vcpu *vcpu;
 
@@ -271,7 +270,7 @@ void __noreturn hyp_panic(void)
 		__sysreg_restore_state_nvhe(host_ctxt);
 	}
 
-	__hyp_do_panic(restore_host, spsr, elr, par);
+	__hyp_do_panic(host_ctxt, spsr, elr, par);
 	unreachable();
 }
 
-- 
2.31.0.rc2.261.g7f71774620-goog

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCH] KVM: arm64: Fix nVHE hyp panic host context restore
  2021-03-15 12:21 ` Andrew Scull
@ 2021-03-15 12:38   ` Greg KH
  -1 siblings, 0 replies; 5+ messages in thread
From: Greg KH @ 2021-03-15 12:38 UTC (permalink / raw)
  To: Andrew Scull; +Cc: kvmarm, maz, kernel-team, stable

On Mon, Mar 15, 2021 at 12:21:36PM +0000, Andrew Scull wrote:
> Commit c4b000c3928d4f20acef79dccf3a65ae3795e0b0 upstream.
> 
> When panicking from the nVHE hyp and restoring the host context, x29 is
> expected to hold a pointer to the host context. This wasn't being done
> so fix it to make sure there's a valid pointer the host context being
> used.
> 
> Rather than passing a boolean indicating whether or not the host context
> should be restored, instead pass the pointer to the host context. NULL
> is passed to indicate that no context should be restored.
> 
> Fixes: a2e102e20fd6 ("KVM: arm64: nVHE: Handle hyp panics")
> Cc: stable@vger.kernel.org # 5.11.y only
> Signed-off-by: Andrew Scull <ascull@google.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@google.com
> ---
>  arch/arm64/include/asm/kvm_hyp.h |  3 ++-
>  arch/arm64/kvm/hyp/nvhe/host.S   | 20 ++++++++++----------
>  arch/arm64/kvm/hyp/nvhe/switch.c |  3 +--
>  3 files changed, 13 insertions(+), 13 deletions(-)

Both backports now queued up, thanks.

greg k-h

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH] KVM: arm64: Fix nVHE hyp panic host context restore
@ 2021-03-15 12:38   ` Greg KH
  0 siblings, 0 replies; 5+ messages in thread
From: Greg KH @ 2021-03-15 12:38 UTC (permalink / raw)
  To: Andrew Scull; +Cc: maz, kernel-team, kvmarm, stable

On Mon, Mar 15, 2021 at 12:21:36PM +0000, Andrew Scull wrote:
> Commit c4b000c3928d4f20acef79dccf3a65ae3795e0b0 upstream.
> 
> When panicking from the nVHE hyp and restoring the host context, x29 is
> expected to hold a pointer to the host context. This wasn't being done
> so fix it to make sure there's a valid pointer the host context being
> used.
> 
> Rather than passing a boolean indicating whether or not the host context
> should be restored, instead pass the pointer to the host context. NULL
> is passed to indicate that no context should be restored.
> 
> Fixes: a2e102e20fd6 ("KVM: arm64: nVHE: Handle hyp panics")
> Cc: stable@vger.kernel.org # 5.11.y only
> Signed-off-by: Andrew Scull <ascull@google.com>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@google.com
> ---
>  arch/arm64/include/asm/kvm_hyp.h |  3 ++-
>  arch/arm64/kvm/hyp/nvhe/host.S   | 20 ++++++++++----------
>  arch/arm64/kvm/hyp/nvhe/switch.c |  3 +--
>  3 files changed, 13 insertions(+), 13 deletions(-)

Both backports now queued up, thanks.

greg k-h
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Patch "KVM: arm64: Fix nVHE hyp panic host context restore" has been added to the 5.11-stable tree
  2021-03-15 12:21 ` Andrew Scull
  (?)
  (?)
@ 2021-03-15 12:38 ` gregkh
  -1 siblings, 0 replies; 5+ messages in thread
From: gregkh @ 2021-03-15 12:38 UTC (permalink / raw)
  To: ascull, gregkh, kernel-team, kvmarm, maz; +Cc: stable-commits


This is a note to let you know that I've just added the patch titled

    KVM: arm64: Fix nVHE hyp panic host context restore

to the 5.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-arm64-fix-nvhe-hyp-panic-host-context-restore.patch
and it can be found in the queue-5.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From foo@baz Mon Mar 15 01:37:54 PM CET 2021
From: Andrew Scull <ascull@google.com>
Date: Mon, 15 Mar 2021 12:21:36 +0000
Subject: KVM: arm64: Fix nVHE hyp panic host context restore
To: kvmarm@lists.cs.columbia.edu
Cc: maz@kernel.org, kernel-team@android.com, Andrew Scull <ascull@google.com>, stable@vger.kernel.org
Message-ID: <20210315122136.1687370-1-ascull@google.com>

From: Andrew Scull <ascull@google.com>

Commit c4b000c3928d4f20acef79dccf3a65ae3795e0b0 upstream.

When panicking from the nVHE hyp and restoring the host context, x29 is
expected to hold a pointer to the host context. This wasn't being done
so fix it to make sure there's a valid pointer the host context being
used.

Rather than passing a boolean indicating whether or not the host context
should be restored, instead pass the pointer to the host context. NULL
is passed to indicate that no context should be restored.

Fixes: a2e102e20fd6 ("KVM: arm64: nVHE: Handle hyp panics")
Cc: stable@vger.kernel.org # 5.11.y only
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/include/asm/kvm_hyp.h |    3 ++-
 arch/arm64/kvm/hyp/nvhe/host.S   |   20 ++++++++++----------
 arch/arm64/kvm/hyp/nvhe/switch.c |    3 +--
 3 files changed, 13 insertions(+), 13 deletions(-)

--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -102,7 +102,8 @@ bool kvm_host_psci_handler(struct kvm_cp
 
 void __noreturn hyp_panic(void);
 #ifdef __KVM_NVHE_HYPERVISOR__
-void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
+void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
+			       u64 elr, u64 par);
 #endif
 
 #endif /* __ARM64_KVM_HYP_H__ */
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -71,10 +71,15 @@ SYM_FUNC_START(__host_enter)
 SYM_FUNC_END(__host_enter)
 
 /*
- * void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
+ * void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
+ * 				  u64 elr, u64 par);
  */
 SYM_FUNC_START(__hyp_do_panic)
-	/* Load the format arguments into x1-7 */
+	mov	x29, x0
+
+	/* Load the format string into x0 and arguments into x1-7 */
+	ldr	x0, =__hyp_panic_string
+
 	mov	x6, x3
 	get_vcpu_ptr x7, x3
 
@@ -89,13 +94,8 @@ SYM_FUNC_START(__hyp_do_panic)
 	ldr	lr, =panic
 	msr	elr_el2, lr
 
-	/*
-	 * Set the panic format string and enter the host, conditionally
-	 * restoring the host context.
-	 */
-	cmp	x0, xzr
-	ldr	x0, =__hyp_panic_string
-	b.eq	__host_enter_without_restoring
+	/* Enter the host, conditionally restoring the host context. */
+	cbz	x29, __host_enter_without_restoring
 	b	__host_enter_for_panic
 SYM_FUNC_END(__hyp_do_panic)
 
@@ -150,7 +150,7 @@ SYM_FUNC_END(__hyp_do_panic)
 
 .macro invalid_host_el1_vect
 	.align 7
-	mov	x0, xzr		/* restore_host = false */
+	mov	x0, xzr		/* host_ctxt = NULL */
 	mrs	x1, spsr_el2
 	mrs	x2, elr_el2
 	mrs	x3, par_el1
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -266,7 +266,6 @@ void __noreturn hyp_panic(void)
 	u64 spsr = read_sysreg_el2(SYS_SPSR);
 	u64 elr = read_sysreg_el2(SYS_ELR);
 	u64 par = read_sysreg_par();
-	bool restore_host = true;
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_vcpu *vcpu;
 
@@ -280,7 +279,7 @@ void __noreturn hyp_panic(void)
 		__sysreg_restore_state_nvhe(host_ctxt);
 	}
 
-	__hyp_do_panic(restore_host, spsr, elr, par);
+	__hyp_do_panic(host_ctxt, spsr, elr, par);
 	unreachable();
 }
 


Patches currently in stable-queue which might be from ascull@google.com are

queue-5.11/kvm-arm64-fix-nvhe-hyp-panic-host-context-restore.patch
queue-5.11/kvm-arm64-avoid-corrupting-vcpu-context-register-in-guest-exit.patch
_______________________________________________
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kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-03-15 12:39 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-15 12:21 [PATCH] KVM: arm64: Fix nVHE hyp panic host context restore Andrew Scull
2021-03-15 12:21 ` Andrew Scull
2021-03-15 12:38 ` Greg KH
2021-03-15 12:38   ` Greg KH
2021-03-15 12:38 ` Patch "KVM: arm64: Fix nVHE hyp panic host context restore" has been added to the 5.11-stable tree gregkh

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