From: Wei Chen <Wei.Chen@arm.com>
To: xen-devel@lists.xen.org
Cc: sstabellini@kernel.org, wei.chen@arm.com, steve.capper@arm.com,
Kaly.Xin@arm.com, julien.grall@arm.com, nd@arm.com
Subject: [PATCH v4 05/19] xen/arm: Save HCR_EL2 when a guest took the SError
Date: Wed, 5 Apr 2017 17:09:07 +0800 [thread overview]
Message-ID: <1491383361-22886-6-git-send-email-Wei.Chen@arm.com> (raw)
In-Reply-To: <1491383361-22886-1-git-send-email-Wei.Chen@arm.com>
The HCR_EL2.VSE (HCR.VA for aarch32) bit can be used to generate a
virtual abort to guest. The HCR_EL2.VSE bit has a peculiar feature
of getting cleared when the guest has taken the abort (this is the
only bit that behaves as such in HCR_EL2 register).
This means that if we set the HCR_EL2.VSE bit to signal such an abort,
we must preserve it in the guest context until it disappears from
HCR_EL2, and at which point it must be cleared from the context. This
is achieved by reading back from HCR_EL2 until the guest takes the
fault.
If we preserved a pending VSE in guest context, we have to restore
it to HCR_EL2 when context switch to this guest. This is achieved
by writing saved HCR_EL2 value in guest context back to HCR_EL2
register before return to guest. This had been done by the patch
of "Restore HCR_EL2 register".
Signed-off-by: Wei Chen <Wei.Chen@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
---
xen/arch/arm/traps.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index ebe25c6..35ca0ed 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2694,7 +2694,18 @@ static void do_trap_smc(struct cpu_user_regs *regs, const union hsr hsr)
static void enter_hypervisor_head(struct cpu_user_regs *regs)
{
if ( guest_mode(regs) )
+ {
+ /*
+ * If we pended a virtual abort, preserve it until it gets cleared.
+ * See ARM ARM DDI 0487A.j D1.14.3 (Virtual Interrupts) for details,
+ * but the crucial bit is "On taking a vSError interrupt, HCR_EL2.VSE
+ * (alias of HCR.VA) is cleared to 0."
+ */
+ if ( current->arch.hcr_el2 & HCR_VA )
+ current->arch.hcr_el2 = READ_SYSREG(HCR_EL2);
+
gic_clear_lrs(current);
+ }
}
asmlinkage void do_trap_hypervisor(struct cpu_user_regs *regs)
--
2.7.4
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next prev parent reply other threads:[~2017-04-05 9:09 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 9:09 [PATCH v4 00/19] Provide a command line option to choose how to handle SErrors Wei Chen
2017-04-05 9:09 ` [PATCH v4 01/19] xen/arm: Save ESR_EL2 to avoid using mismatched value in syndrome check Wei Chen
2017-04-05 9:09 ` [PATCH v4 02/19] xen/arm: Introduce a helper to get default HCR_EL2 flags Wei Chen
2017-04-05 9:09 ` [PATCH v4 03/19] xen/arm: Set and restore HCR_EL2 register for each vCPU separately Wei Chen
2017-04-05 9:09 ` [PATCH v4 04/19] xen/arm: Avoid setting/clearing HCR_RW at every context switch Wei Chen
2017-04-05 9:09 ` Wei Chen [this message]
2017-04-05 9:09 ` [PATCH v4 06/19] xen/arm: Introduce a virtual abort injection helper Wei Chen
2017-04-05 9:09 ` [PATCH v4 07/19] xen/arm: Introduce a command line parameter for SErrors/Aborts Wei Chen
2017-04-05 9:09 ` [PATCH v4 08/19] xen/arm: Introduce a initcall to update cpu_hwcaps by serror_op Wei Chen
2017-04-05 9:09 ` [PATCH v4 09/19] xen/arm64: Use alternative to skip the check of pending serrors Wei Chen
2017-04-05 9:09 ` [PATCH v4 10/19] xen/arm32: " Wei Chen
2017-04-05 9:09 ` [PATCH v4 11/19] xen/arm: Move macro VABORT_GEN_BY_GUEST to common header Wei Chen
2017-04-05 9:09 ` [PATCH v4 12/19] xen/arm: Introduce new helpers to handle guest/hyp SErrors Wei Chen
2017-04-05 9:09 ` [PATCH v4 13/19] xen/arm: Replace do_trap_guest_serror with new helpers Wei Chen
2017-04-05 9:09 ` [PATCH v4 14/19] xen/arm: Unmask the Abort/SError bit in the exception entries Wei Chen
2017-04-05 9:09 ` [PATCH v4 15/19] xen/arm: Introduce a helper to check local abort is enabled Wei Chen
2017-04-05 11:14 ` Julien Grall
2017-04-05 9:09 ` [PATCH v4 16/19] xen/arm: Introduce a macro to synchronize SError Wei Chen
2017-04-05 11:15 ` Julien Grall
2017-04-05 9:09 ` [PATCH v4 17/19] xen/arm: Isolate the SError between the context switch of 2 vCPUs Wei Chen
2017-04-05 9:09 ` [PATCH v4 18/19] xen/arm: Prevent slipping hypervisor SError to guest Wei Chen
2017-04-05 11:17 ` Julien Grall
2017-04-05 9:09 ` [PATCH v4 19/19] xen/arm: Handle guest external abort as guest SError Wei Chen
2017-04-05 19:18 ` [PATCH v4 00/19] Provide a command line option to choose how to handle SErrors Stefano Stabellini
2017-04-06 4:52 ` Wei Chen
2017-04-07 15:37 ` Julien Grall
2017-04-07 23:20 ` Stefano Stabellini
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