From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
From: Andrew Scull <ascull@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx # 5.11.y only
Signed-off-by: Andrew Scull <ascull@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210219122406.1337626-1-ascull@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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();
}
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