On Mon, 13 Mar 2017, Wei Chen wrote:
> Currently, ARM32 and ARM64 has different SError exception handlers.
> These handlers include lots of code to check SError handle options
> and code to distinguish guest-generated SErrors from hypervisor
> SErrors.
>
> The new helpers: do_trap_guest_serror and do_trap_hyp_serror are
> wrappers of __do_trap_serror with constant guest/hyp parameters.
> __do_trap_serror moves the option checking code and SError checking
> code from assembly to C source. This will make the code become more
> readable and avoid placing check code in too many places.
>
> These two helpers only handle the following 3 types of SErrors:
> 1) Guest-generated SError and had been delivered in EL1 and then
> been forwarded to EL2.
> 2) Guest-generated SError but hadn't been delivered in EL1 before
> trapping to EL2. This SError would be caught in EL2 as soon as
> we just unmasked the PSTATE.A bit.
> 3) Hypervisor generated native SError, that would be a bug.
>
> In the new helpers, we have used the function "inject_vabt_exception"
> which was disabled by "#if 0" before. Now, we can remove the "#if 0"
> to make this function to be available.
>
> Signed-off-by: Wei Chen <wei.c...@arm.com>
Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
> ---
> xen/arch/arm/traps.c | 69
> +++++++++++++++++++++++++++++++++++++++--
> xen/include/asm-arm/processor.h | 4 +++
> 2 files changed, 71 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index 053b7fc..48cfc8e 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -646,7 +646,6 @@ static void inject_dabt_exception(struct cpu_user_regs
> *regs,
> #endif
> }
>
> -#if 0
> /* Inject a virtual Abort/SError into the guest. */
> static void inject_vabt_exception(struct cpu_user_regs *regs)
> {
> @@ -676,7 +675,59 @@ static void inject_vabt_exception(struct cpu_user_regs
> *regs)
>
> current->arch.hcr_el2 |= HCR_VA;
> }
> -#endif
> +
> +/*
> + * SError exception handler. We only handle the following 3 types of SErrors:
> + * 1) Guest-generated SError and had been delivered in EL1 and then
> + * been forwarded to EL2.
> + * 2) Guest-generated SError but hadn't been delivered in EL1 before
> + * trapping to EL2. This SError would be caught in EL2 as soon as
> + * we just unmasked the PSTATE.A bit.
> + * 3) Hypervisor generated native SError, that would be a bug.
> + *
> + * A true parameter "guest" means that the SError is type#1 or type#2.
> + */
> +static void __do_trap_serror(struct cpu_user_regs *regs, bool guest)
> +{
> + /*
> + * Only "DIVERSE" option needs to distinguish the guest-generated SErrors
> + * from hypervisor SErrors.
> + */
> + if ( serrors_op == SERRORS_DIVERSE )
> + {
> + /* Forward the type#1 and type#2 SErrors to guests. */
> + if ( guest )
> + return inject_vabt_exception(regs);
> +
> + /* Type#3 SErrors will panic the whole system */
> + goto crash_system;
> + }
> +
> + /*
> + * The "FORWARD" option will forward all SErrors to the guests, except
> + * idle domain generated SErrors.
> + */
> + if ( serrors_op == SERRORS_FORWARD )
> + {
> + /*
> + * Because the idle domain doesn't have the ability to handle the
> + * SErrors, we have to crash the whole system while we get a SError
> + * generated by idle domain.
> + */
> + if ( is_idle_vcpu(current) )
> + goto crash_system;
> +
> + return inject_vabt_exception(regs);
> + }
> +
> +crash_system:
> + /* Three possibilities to crash the whole system:
> + * 1) "DIVERSE" option with Hypervisor generated SErrors.
> + * 2) "FORWARD" option with Idle Domain generated SErrors.
> + * 3) "PANIC" option with all SErrors.
> + */
> + do_unexpected_trap("SError", regs);
> +}
>
> struct reg_ctxt {
> /* Guest-side state */
> @@ -2863,6 +2914,20 @@ asmlinkage void do_trap_guest_error(struct
> cpu_user_regs *regs)
> domain_crash_synchronous();
> }
>
> +asmlinkage void do_trap_hyp_serror(struct cpu_user_regs *regs)
> +{
> + enter_hypervisor_head(regs);
> +
> + __do_trap_serror(regs, VABORT_GEN_BY_GUEST(regs));
> +}
> +
> +asmlinkage void do_trap_guest_serror(struct cpu_user_regs *regs)
> +{
> + enter_hypervisor_head(regs);
> +
> + __do_trap_serror(regs, true);
> +}
> +
> asmlinkage void do_trap_irq(struct cpu_user_regs *regs)
> {
> enter_hypervisor_head(regs);
> diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
> index 148cc6f..885dbca 100644
> --- a/xen/include/asm-arm/processor.h
> +++ b/xen/include/asm-arm/processor.h
> @@ -709,6 +709,10 @@ int call_smc(register_t function_id, register_t arg0,
> register_t arg1,
>
> void do_trap_guest_error(struct cpu_user_regs *regs);
>
> +void do_trap_hyp_serror(struct cpu_user_regs *regs);
> +
> +void do_trap_guest_serror(struct cpu_user_regs *regs);
> +
> /* Functions for pending virtual abort checking window. */
> void abort_guest_exit_start(void);
> void abort_guest_exit_end(void);
> --
> 2.7.4
>
>
> _______________________________________________
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> Xen-devel@lists.xen.org
> https://lists.xen.org/xen-devel
>
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