From: Stefano Stabellini <sstabellini@kernel.org>
To: Wei Chen <Wei.Chen@arm.com>
Cc: sstabellini@kernel.org, steve.capper@arm.com,
xen-devel@lists.xen.org, Kaly.Xin@arm.com, julien.grall@arm.com,
nd@arm.com
Subject: Re: [PATCH v3 16/19] xen/arm: Introduce a macro to synchronize SError
Date: Fri, 31 Mar 2017 11:36:37 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.10.1703311136210.2723@sstabellini-ThinkPad-X260> (raw)
In-Reply-To: <1490965679-619-17-git-send-email-Wei.Chen@arm.com>
On Fri, 31 Mar 2017, Wei Chen wrote:
> In previous patches, we have provided the ability to synchronize
> SErrors in exception entries. But we haven't synchronized SErrors
> while returning to guest and doing context switch.
>
> So we still have two risks:
> 1. Slipping hypervisor SErrors to guest. For example, hypervisor
> triggers a SError while returning to guest, but this SError may be
> delivered after entering guest. In "DIVERSE" option, this SError
> would be routed back to guest and panic the guest. But actually,
> we should crash the whole system due to this hypervisor SError.
> 2. Slipping previous guest SErrors to the next guest. In "FORWARD"
> option, if hypervisor triggers a SError while context switching.
> This SError may be delivered after switching to next vCPU. In this
> case, this SError will be forwarded to next vCPU and may panic
> an incorrect guest.
>
> So we have have to introduce this macro to synchronize SErrors while
> returning to guest and doing context switch.
>
> We also added a barrier to this macro to prevent compiler reorder our
> asm volatile code.
>
> Signed-off-by: Wei Chen <Wei.Chen@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> ---
> v2->v3:
> 1. Use a macro to replace function to synchronize SErrors.
> 2. Add barrier to avoid compiler reorder our code.
>
> Note:
> I had followed Julien's suggestion to add the Assert in to macro,
> But I found I always hit the Assert. Because when option == DIVERSE,
> the SKIP_CHECK_PENDING_VSERROR feature would not be set into cpu_hwcaps.
> And in the later patch, I will use this feature to skip synchronize
> SErrors before returning to guest.
> The cpus_has_cap(SKIP_CHECK_PENDING_VSERROR) will always false.
> And hit the ASSERT.
>
> And about the local_abort enable check, should we disable the abort
> before synchronizing SErrors while returning to guest or doing context
> switch? Just like in these two places we have disable the IRQ.
>
> For this testing, I have apply this series to latest staging tree.
>
> ...
> (XEN) Command line: console=dtuart dtuart=serial0 conswitch=x loglvl=all
> dom0_mem=8G dom0_max_vcpus=8 serrors=diverse
> (XEN) Placing Xen at 0x00000083fee00000-0x00000083ff000000
> ...
> (XEN) ----SYNCHRONIZE_SERROR ASSERT 0 1
> (XEN) Assertion 'cpus_have_cap(5) && local_abort_is_enabled()' failed at
> traps.c:2954
> (XEN) ----[ Xen-4.9-unstable arm64 debug=y Not tainted ]----
> (XEN) CPU: 0
> (XEN) PC: 000000000025c09c leave_hypervisor_tail+0xa8/0x100
> (XEN) LR: 000000000025c078
> (XEN) SP: 00008003fac07e80
> (XEN) CPSR: 800002c9 MODE:64-bit EL2h (Hypervisor, handler)
> (XEN) X0: 000000000000005a X1: 00000000ffffffff X2:
> 0000000000000000
> (XEN) X3: 0000000000000000 X4: 0000000000000010 X5:
> 0000000000000000
> (XEN) X6: 00008003ffe50000 X7: 0000000000000001 X8:
> 00000000fffffffd
> (XEN) X9: 000000000000000a X10: 0000000000000031 X11:
> 00008003fac07bf8
> (XEN) X12: 0000000000000001 X13: 000000000026c370 X14:
> 0000000000000020
> (XEN) X15: 0000000000000000 X16: 00000083fff42fc0 X17:
> 00000000fffffffe
> (XEN) X18: 0000000000000000 X19: 0000000000292c58 X20:
> 0000000000290028
> (XEN) X21: 00000000002ea000 X22: 0000000000000000 X23:
> 0000000000000000
> (XEN) X24: 0000000000000000 X25: 0000000000000000 X26:
> 0000000000000000
> (XEN) X27: 0000000000000000 X28: 0000000000000000 FP:
> 00008003fac07e80
> (XEN)
> (XEN) VTCR_EL2: 80043594
> (XEN) VTTBR_EL2: 00010083fd036000
> (XEN)
> (XEN) SCTLR_EL2: 30cd183d
> (XEN) HCR_EL2: 000000008038663f
> (XEN) TTBR0_EL2: 00000083fef0e000
> (XEN)
> (XEN) ESR_EL2: f2000001
> (XEN) HPFAR_EL2: 0000000000000000
> (XEN) FAR_EL2: 0000000000000000
> (XEN)
> (XEN) Xen stack trace from sp=00008003fac07e80:
> (XEN) 00008003fac07ea0 0000000000262934 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000249cac 0000008048000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000008040080000
> 00000000000001c5
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) 0000000000000000 0000000000000000 0000000000000000
> 0000000000000000
> (XEN) Xen call trace:
> (XEN) [<000000000025c09c>] leave_hypervisor_tail+0xa8/0x100 (PC)
> (XEN) [<000000000025c078>] leave_hypervisor_tail+0x84/0x100 (LR)
> (XEN) [<0000000000262934>] return_to_new_vcpu64+0x4/0x30
> (XEN) [<0000000000249cac>] domain.c#continue_new_vcpu+0/0xa4
> (XEN)
> (XEN)
> (XEN) ****************************************
> (XEN) Panic on CPU 0:
> (XEN) Assertion 'cpus_have_cap(5) && local_abort_is_enabled()' failed at
> traps.c:2954
> (XEN) ****************************************
> (XEN)
> (XEN) Reboot in five seconds...
> ---
> xen/include/asm-arm/processor.h | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
> index bb24bee..a787d1b 100644
> --- a/xen/include/asm-arm/processor.h
> +++ b/xen/include/asm-arm/processor.h
> @@ -723,6 +723,17 @@ void abort_guest_exit_end(void);
> ( (unsigned long)abort_guest_exit_end == (r)->pc ) \
> )
>
> +/*
> + * Synchronize SError unless the feature is selected.
> + * This is relying on the SErrors are currently unmasked.
> + */
> +#define SYNCHRONIZE_SERROR(feat) \
> + do { \
> + asm volatile(ALTERNATIVE("dsb sy; isb", \
> + "nop; nop", feat) \
> + : : : "memory"); \
> + } while (0)
> +
> #endif /* __ASSEMBLY__ */
> #endif /* __ASM_ARM_PROCESSOR_H */
> /*
> --
> 2.7.4
>
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next prev parent reply other threads:[~2017-03-31 18:36 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-31 13:07 [PATCH v3 00/19] Provide a command line option to choose how to handle SErrors Wei Chen
2017-03-31 13:07 ` [PATCH v3 01/19] xen/arm: Save ESR_EL2 to avoid using mismatched value in syndrome check Wei Chen
2017-03-31 14:08 ` Julien Grall
2017-03-31 18:26 ` Stefano Stabellini
2017-03-31 13:07 ` [PATCH v3 02/19] xen/arm: Introduce a helper to get default HCR_EL2 flags Wei Chen
2017-03-31 14:10 ` Julien Grall
2017-03-31 18:29 ` Stefano Stabellini
2017-03-31 13:07 ` [PATCH v3 03/19] xen/arm: Set and restore HCR_EL2 register for each vCPU separately Wei Chen
2017-03-31 14:11 ` Julien Grall
2017-03-31 18:28 ` Stefano Stabellini
2017-03-31 13:07 ` [PATCH v3 04/19] xen/arm: Avoid setting/clearing HCR_RW at every context switch Wei Chen
2017-03-31 13:07 ` [PATCH v3 05/19] xen/arm: Save HCR_EL2 when a guest took the SError Wei Chen
2017-03-31 13:07 ` [PATCH v3 06/19] xen/arm: Introduce a virtual abort injection helper Wei Chen
2017-03-31 14:13 ` Julien Grall
2017-03-31 13:07 ` [PATCH v3 07/19] xen/arm: Introduce a command line parameter for SErrors/Aborts Wei Chen
2017-03-31 13:07 ` [PATCH v3 08/19] xen/arm: Introduce a initcall to update cpu_hwcaps by serror_op Wei Chen
2017-03-31 14:48 ` Julien Grall
2017-04-05 6:36 ` Wei Chen
2017-03-31 13:07 ` [PATCH v3 09/19] xen/arm64: Use alternative to skip the check of pending serrors Wei Chen
2017-03-31 13:07 ` [PATCH v3 10/19] xen/arm32: " Wei Chen
2017-03-31 13:07 ` [PATCH v3 11/19] xen/arm: Move macro VABORT_GEN_BY_GUEST to common header Wei Chen
2017-03-31 13:07 ` [PATCH v3 12/19] xen/arm: Introduce new helpers to handle guest/hyp SErrors Wei Chen
2017-03-31 13:07 ` [PATCH v3 13/19] xen/arm: Replace do_trap_guest_serror with new helpers Wei Chen
2017-03-31 13:07 ` [PATCH v3 14/19] xen/arm: Unmask the Abort/SError bit in the exception entries Wei Chen
2017-03-31 13:07 ` [PATCH v3 15/19] xen/arm: Introduce a helper to check local abort is enabled Wei Chen
2017-03-31 14:25 ` Julien Grall
2017-03-31 18:43 ` Stefano Stabellini
2017-03-31 13:07 ` [PATCH v3 16/19] xen/arm: Introduce a macro to synchronize SError Wei Chen
2017-03-31 14:33 ` Julien Grall
2017-04-05 7:14 ` Wei Chen
2017-04-05 7:29 ` Julien Grall
2017-04-05 7:35 ` Wei Chen
2017-04-05 8:02 ` Julien Grall
2017-04-05 8:08 ` Wei Chen
2017-04-05 8:20 ` Julien Grall
2017-04-05 8:32 ` Wei Chen
2017-03-31 18:36 ` Stefano Stabellini [this message]
2017-03-31 13:07 ` [PATCH v3 17/19] xen/arm: Isolate the SError between the context switch of 2 vCPUs Wei Chen
2017-03-31 14:38 ` Julien Grall
2017-03-31 18:37 ` Stefano Stabellini
2017-03-31 13:07 ` [PATCH v3 18/19] xen/arm: Prevent slipping hypervisor SError to guest Wei Chen
2017-03-31 14:46 ` Julien Grall
2017-03-31 18:42 ` Stefano Stabellini
2017-03-31 18:43 ` Julien Grall
2017-04-05 7:15 ` Wei Chen
2017-03-31 13:07 ` [PATCH v3 19/19] xen/arm: Handle guest external abort as guest SError Wei Chen
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