KVM: arm64: Restore hyp when panicking in guest context

[mirror_ubuntu-hirsute-kernel.git] / arch / arm64 / kvm / hyp / entry.S

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 38cca690a6ff54f0f00e309892ad11d2adeccab8..4787fc82790cb078f22e553176b71cca3352a004 100644 (file)
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -86,6 +86,8 @@ alternative_else_nop_endif
        ret
 
 1:
+       set_loaded_vcpu x0, x1, x2
+
        add     x29, x0, #VCPU_CONTEXT
 
        // Macro ptrauth_switch_to_guest format:
@@ -116,6 +118,26 @@ alternative_else_nop_endif
        eret
        sb
 
+SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL)
+       // x2-x29,lr: vcpu regs
+       // vcpu x0-x1 on the stack
+
+       // If the hyp context is loaded, go straight to hyp_panic
+       get_loaded_vcpu x0, x1
+       cbz     x0, hyp_panic
+
+       // The hyp context is saved so make sure it is restored to allow
+       // hyp_panic to run at hyp and, subsequently, panic to run in the host.
+       // This makes use of __guest_exit to avoid duplication but sets the
+       // return address to tail call into hyp_panic. As a side effect, the
+       // current state is saved to the guest context but it will only be
+       // accurate if the guest had been completely restored.
+       hyp_adr_this_cpu x0, kvm_hyp_ctxt, x1
+       adr     x1, hyp_panic
+       str     x1, [x0, #CPU_XREG_OFFSET(30)]
+
+       get_vcpu_ptr    x1, x0
+
 SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL)
        // x0: return code
        // x1: vcpu
@@ -163,6 +185,8 @@ SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL)
        // Now restore the hyp regs
        restore_callee_saved_regs x2
 
+       set_loaded_vcpu xzr, x1, x2
+
 alternative_if ARM64_HAS_RAS_EXTN
        // If we have the RAS extensions we can consume a pending error
        // without an unmask-SError and isb. The ESB-instruction consumed any