1 files changed, 80 insertions, 48 deletions

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index ce9e5e5f28cf..12ee62d6d410 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -55,79 +55,111 @@
  */
 ENTRY(__guest_enter)
 	// x0: vcpu
-	// x1: host/guest context
-	// x2-x18: clobbered by macros
+	// x1: host context
+	// x2-x17: clobbered by macros
+	// x18: guest context
 
 	// Store the host regs
 	save_callee_saved_regs x1
 
-	// Preserve vcpu & host_ctxt for use at exit time
-	stp	x0, x1, [sp, #-16]!
+	// Store the host_ctxt for use at exit time
+	str	x1, [sp, #-16]!
 
-	add	x1, x0, #VCPU_CONTEXT
+	add	x18, x0, #VCPU_CONTEXT
 
-	// Prepare x0-x1 for later restore by pushing them onto the stack
-	ldp	x2, x3, [x1, #CPU_XREG_OFFSET(0)]
-	stp	x2, x3, [sp, #-16]!
+	// Restore guest regs x0-x17
+	ldp	x0, x1,   [x18, #CPU_XREG_OFFSET(0)]
+	ldp	x2, x3,   [x18, #CPU_XREG_OFFSET(2)]
+	ldp	x4, x5,   [x18, #CPU_XREG_OFFSET(4)]
+	ldp	x6, x7,   [x18, #CPU_XREG_OFFSET(6)]
+	ldp	x8, x9,   [x18, #CPU_XREG_OFFSET(8)]
+	ldp	x10, x11, [x18, #CPU_XREG_OFFSET(10)]
+	ldp	x12, x13, [x18, #CPU_XREG_OFFSET(12)]
+	ldp	x14, x15, [x18, #CPU_XREG_OFFSET(14)]
+	ldp	x16, x17, [x18, #CPU_XREG_OFFSET(16)]
 
-	// x2-x18
-	ldp	x2, x3,   [x1, #CPU_XREG_OFFSET(2)]
-	ldp	x4, x5,   [x1, #CPU_XREG_OFFSET(4)]
-	ldp	x6, x7,   [x1, #CPU_XREG_OFFSET(6)]
-	ldp	x8, x9,   [x1, #CPU_XREG_OFFSET(8)]
-	ldp	x10, x11, [x1, #CPU_XREG_OFFSET(10)]
-	ldp	x12, x13, [x1, #CPU_XREG_OFFSET(12)]
-	ldp	x14, x15, [x1, #CPU_XREG_OFFSET(14)]
-	ldp	x16, x17, [x1, #CPU_XREG_OFFSET(16)]
-	ldr	x18,      [x1, #CPU_XREG_OFFSET(18)]
-
-	// x19-x29, lr
-	restore_callee_saved_regs x1
-
-	// Last bits of the 64bit state
-	ldp	x0, x1, [sp], #16
+	// Restore guest regs x19-x29, lr
+	restore_callee_saved_regs x18
+
+	// Restore guest reg x18
+	ldr	x18,      [x18, #CPU_XREG_OFFSET(18)]
 
 	// Do not touch any register after this!
 	eret
 ENDPROC(__guest_enter)
 
 ENTRY(__guest_exit)
-	// x0: vcpu
-	// x1: return code
-	// x2-x3: free
-	// x4-x29,lr: vcpu regs
-	// vcpu x0-x3 on the stack
+	// x0: return code
+	// x1: vcpu
+	// x2-x29,lr: vcpu regs
+	// vcpu x0-x1 on the stack
 
-	add	x2, x0, #VCPU_CONTEXT
+	add	x1, x1, #VCPU_CONTEXT
 
-	stp	x4, x5,   [x2, #CPU_XREG_OFFSET(4)]
-	stp	x6, x7,   [x2, #CPU_XREG_OFFSET(6)]
-	stp	x8, x9,   [x2, #CPU_XREG_OFFSET(8)]
-	stp	x10, x11, [x2, #CPU_XREG_OFFSET(10)]
-	stp	x12, x13, [x2, #CPU_XREG_OFFSET(12)]
-	stp	x14, x15, [x2, #CPU_XREG_OFFSET(14)]
-	stp	x16, x17, [x2, #CPU_XREG_OFFSET(16)]
-	str	x18,      [x2, #CPU_XREG_OFFSET(18)]
+	ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
 
-	ldp	x6, x7, [sp], #16	// x2, x3
-	ldp	x4, x5, [sp], #16	// x0, x1
+	// Store the guest regs x2 and x3
+	stp	x2, x3,   [x1, #CPU_XREG_OFFSET(2)]
 
-	stp	x4, x5, [x2, #CPU_XREG_OFFSET(0)]
-	stp	x6, x7, [x2, #CPU_XREG_OFFSET(2)]
+	// Retrieve the guest regs x0-x1 from the stack
+	ldp	x2, x3, [sp], #16	// x0, x1
+
+	// Store the guest regs x0-x1 and x4-x18
+	stp	x2, x3,   [x1, #CPU_XREG_OFFSET(0)]
+	stp	x4, x5,   [x1, #CPU_XREG_OFFSET(4)]
+	stp	x6, x7,   [x1, #CPU_XREG_OFFSET(6)]
+	stp	x8, x9,   [x1, #CPU_XREG_OFFSET(8)]
+	stp	x10, x11, [x1, #CPU_XREG_OFFSET(10)]
+	stp	x12, x13, [x1, #CPU_XREG_OFFSET(12)]
+	stp	x14, x15, [x1, #CPU_XREG_OFFSET(14)]
+	stp	x16, x17, [x1, #CPU_XREG_OFFSET(16)]
+	str	x18,      [x1, #CPU_XREG_OFFSET(18)]
+
+	// Store the guest regs x19-x29, lr
+	save_callee_saved_regs x1
 
-	save_callee_saved_regs x2
+	// Restore the host_ctxt from the stack
+	ldr	x2, [sp], #16
 
-	// Restore vcpu & host_ctxt from the stack
-	// (preserving return code in x1)
-	ldp	x0, x2, [sp], #16
 	// Now restore the host regs
 	restore_callee_saved_regs x2
 
-	mov	x0, x1
-	ret
+	// If we have a pending asynchronous abort, now is the
+	// time to find out. From your VAXorcist book, page 666:
+	// "Threaten me not, oh Evil one!  For I speak with
+	// the power of DEC, and I command thee to show thyself!"
+	mrs	x2, elr_el2
+	mrs	x3, esr_el2
+	mrs	x4, spsr_el2
+	mov	x5, x0
+
+	dsb	sy		// Synchronize against in-flight ld/st
+	msr	daifclr, #4	// Unmask aborts
+
+	// This is our single instruction exception window. A pending
+	// SError is guaranteed to occur at the earliest when we unmask
+	// it, and at the latest just after the ISB.
+	.global	abort_guest_exit_start
+abort_guest_exit_start:
+
+	isb
+
+	.global	abort_guest_exit_end
+abort_guest_exit_end:
+
+	// If the exception took place, restore the EL1 exception
+	// context so that we can report some information.
+	// Merge the exception code with the SError pending bit.
+	tbz	x0, #ARM_EXIT_WITH_SERROR_BIT, 1f
+	msr	elr_el2, x2
+	msr	esr_el2, x3
+	msr	spsr_el2, x4
+	orr	x0, x0, x5
+1:	ret
 ENDPROC(__guest_exit)
 
 ENTRY(__fpsimd_guest_restore)
+	stp	x2, x3, [sp, #-16]!
 	stp	x4, lr, [sp, #-16]!
 
 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN