On 24/03/17 14:33, Christoffer Dall wrote: > On Tue, Mar 21, 2017 at 07:20:35PM +0000, Marc Zyngier wrote: >> In order to restore HYP mode to its original condition, KVM currently >> implements __kvm_hyp_reset(). As we're moving towards a hyp-stub >> defined API, it becomes necessary to implement HVC_RESET_VECTORS. >> >> This patch adds the HVC_RESET_VECTORS hypercall to the KVM init >> code, which so far lacked any form of hypercall support. >> >> Reviewed-by: James Morse <james.morse@xxxxxxx> >> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> >> --- >> arch/arm64/kvm/hyp-init.S | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) >> >> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S >> index 6b29d3d9e1f2..6cf98ccd10f2 100644 >> --- a/arch/arm64/kvm/hyp-init.S >> +++ b/arch/arm64/kvm/hyp-init.S >> @@ -22,6 +22,7 @@ >> #include <asm/kvm_mmu.h> >> #include <asm/pgtable-hwdef.h> >> #include <asm/sysreg.h> >> +#include <asm/virt.h> >> >> .text >> .pushsection .hyp.idmap.text, "ax" >> @@ -58,6 +59,9 @@ __invalid: >> * x2: HYP vectors >> */ >> __do_hyp_init: >> + /* Check for a stub HVC call */ >> + cmp x0, #HVC_STUB_HCALL_NR >> + b.lo __kvm_handle_stub_hvc >> >> msr ttbr0_el2, x0 >> >> @@ -119,6 +123,9 @@ __do_hyp_init: >> eret >> ENDPROC(__kvm_hyp_init) >> >> +ENTRY(__kvm_handle_stub_hvc) >> + cmp x0, #HVC_RESET_VECTORS >> + b.ne 1f >> /* >> * Reset kvm back to the hyp stub. >> */ >> @@ -133,9 +140,14 @@ ENTRY(__kvm_hyp_reset) >> /* Install stub vectors */ >> adr_l x0, __hyp_stub_vectors >> msr vbar_el2, x0 >> + b exit >> >> +1: mov x0, #-1 > > nit: do we have the -1 return value documented somewhere and should we > define it as HVC_SUB_ERR_RETURN or something like that? Indeed, this is something that is a bit dodgy. arm64 returns ARM_EXCEPTION_HYP_GONE, which is really a KVM exception code (and isn't -1 either). I'll try to tighten this up a bit. Thanks, M. -- Jazz is not dead. It just smells funny...
