From: Andrew Scull ascull@google.com

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 Signed-off-by: Andrew Scull ascull@google.com [maz: partial rewrite to fit 5.12-rc1] 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 | 15 ++++++++------- arch/arm64/kvm/hyp/nvhe/switch.c | 3 +-- 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 385bd7dd3d39..32ae676236b6 100644 --- 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_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 6585a7cbbc56..5d94584840cc 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -71,7 +71,8 @@ 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) /* Prepare and exit to the host's panic funciton. */ @@ -82,9 +83,11 @@ SYM_FUNC_START(__hyp_do_panic) hyp_kimg_va lr, x6 msr elr_el2, lr

- /* Set the panic format string. Use the, now free, LR as scratch. */ - ldr lr, =__hyp_panic_string - hyp_kimg_va lr, x6 + mov x29, x0 + + /* Load the format string into x0 and arguments into x1-7 */ + ldr x0, =__hyp_panic_string + hyp_kimg_va x0, x6

/* Load the format arguments into x1-7. */ mov x6, x3 @@ -94,9 +97,7 @@ SYM_FUNC_START(__hyp_do_panic) mrs x5, hpfar_el2

/* Enter the host, conditionally restoring the host context. */ - cmp x0, xzr - mov x0, lr - b.eq __host_enter_without_restoring + cbz x29, __host_enter_without_restoring b __host_enter_for_panic SYM_FUNC_END(__hyp_do_panic)

diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 59aa1045fdaf..68ab6b4d5141 100644 --- 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(); }