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Commit 4baa1d87 authored by Paul Mackerras's avatar Paul Mackerras Committed by Alexander Graf
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KVM: PPC: Book3S HV: Allow negative offsets to real-mode hcall handlers 



The table of offsets to real-mode hcall handlers in book3s_hv_rmhandlers.S
can contain negative values, if some of the handlers end up before the
table in the vmlinux binary.  Thus we need to use a sign-extending load
to read the values in the table rather than a zero-extending load.
Without this, the host crashes when the guest does one of the hcalls
with negative offsets, due to jumping to a bogus address.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent 54480501

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+1 −1
Original line number Diff line number Diff line
@@ -1381,7 +1381,7 @@ hcall_try_real_mode: 
	cmpldi	r3,hcall_real_table_end - hcall_real_table

	bge	guest_exit_cont

	LOAD_REG_ADDR(r4, hcall_real_table)

	lwzx	r3,r3,r4

	lwax	r3,r3,r4

	cmpwi	r3,0

	beq	guest_exit_cont

	add	r3,r3,r4