diff options
| author | Andrew Scull <ascull@google.com> | 2020-09-15 11:46:34 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2020-09-15 18:39:02 +0100 |
| commit | 7db21530479f071ee0e0a4d5fcf5e6bc6c0352ba (patch) | |
| tree | b82fcec803426f124714480a6973972293016416 /arch/arm64/kvm/hyp/entry.S | |
| parent | 7c2e76d87f9ce7af47a07ca803343fd5f4aa4ab5 (diff) | |
KVM: arm64: Restore hyp when panicking in guest context
If the guest context is loaded when a panic is triggered, restore the
hyp context so e.g. the shadow call stack works when hyp_panic() is
called and SP_EL0 is valid when the host's panic() is called.
Use the hyp context's __hyp_running_vcpu field to track when hyp
transitions to and from the guest vcpu so the exception handlers know
whether the context needs to be restored.
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-11-ascull@google.com
Diffstat (limited to 'arch/arm64/kvm/hyp/entry.S')
| -rw-r--r-- | arch/arm64/kvm/hyp/entry.S | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index 38cca690a6ff..4787fc82790c 100644 --- 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 |