From: Julien Grall <julien.grall@arm.com>
To: xen-devel@lists.xen.org
Cc: andre.przywara@arm.com, Julien Grall <julien.grall@arm.com>,
sstabellini@kernel.org, wei.chen@arm.com, steve.capper@arm.com
Subject: [PATCH v3 15/16] xen/arm: traps: Don't inject a fault if the translation VA -> IPA fails
Date: Tue, 7 Jun 2016 17:06:22 +0100 [thread overview]
Message-ID: <1465315583-1278-16-git-send-email-julien.grall@arm.com> (raw)
In-Reply-To: <1465315583-1278-1-git-send-email-julien.grall@arm.com>
Based on ARM ARM (D4.5.3 in ARM DDI 0486A and B3.12.7 in ARM DDI 0406C.c),
a Stage 1 translation error has priority over a Stage 2 translation error.
Therefore gva_to_ipa can only fail if another vCPU is playing with the
page table.
Rather than injecting a custom fault, replay the instruction and let the
processor injecting the correct fault.
This is fine as Xen is handling all the pending softirqs
(see leave_hypervisor_tail) before returning to the guest. One of them
is the scheduler which could reschuled the vCPU.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---
Changes in v3:
- Add Stefano's acked-by
Changes in v2:
- Update commit message to explain why a guest cannot DoS the
hypervisor with it.
---
xen/arch/arm/traps.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index a4eedca..175033b 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2408,7 +2408,7 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
rc = gva_to_ipa(gva, &gpa, GV2M_READ);
if ( rc == -EFAULT )
- goto bad_insn_abort;
+ return; /* Try again */
}
rc = p2m_mem_access_check(gpa, gva, npfec);
@@ -2420,7 +2420,6 @@ static void do_trap_instr_abort_guest(struct cpu_user_regs *regs,
break;
}
-bad_insn_abort:
inject_iabt_exception(regs, gva, hsr.len);
}
@@ -2450,7 +2449,7 @@ static void do_trap_data_abort_guest(struct cpu_user_regs *regs,
{
rc = gva_to_ipa(info.gva, &info.gpa, GV2M_READ);
if ( rc == -EFAULT )
- goto bad_data_abort;
+ return; /* Try again */
}
switch ( dabt.dfsc & 0x3f )
--
1.9.1
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next prev parent reply other threads:[~2016-06-07 16:06 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 16:06 [PATCH v3 00/16] xen/arm: Introduce alternative runtime patching for ARM64 Julien Grall
2016-06-07 16:06 ` [PATCH v3 01/16] xen/arm: Makefile: Sort the entries alphabetically Julien Grall
2016-06-07 16:06 ` [PATCH v3 02/16] xen/arm: Include the header asm-arm/system.h in asm-arm/page.h Julien Grall
2016-06-07 16:06 ` [PATCH v3 03/16] xen/arm: Add macros to handle the MIDR Julien Grall
2016-06-07 16:06 ` [PATCH v3 04/16] xen/arm: Add cpu_hwcap bitmap Julien Grall
2016-06-07 16:06 ` [PATCH v3 05/16] xen/arm64: Add an helper to invalidate all instruction caches Julien Grall
2016-06-07 16:06 ` [PATCH v3 06/16] xen/arm: arm64: Move the define BRK_BUG_FRAME into a separate header Julien Grall
2016-06-07 16:06 ` [PATCH v3 07/16] xen/arm: arm64: Reserve a brk immediate to fault on purpose Julien Grall
2016-06-07 16:06 ` [PATCH v3 08/16] xen/arm: arm64: Add helpers to decode and encode branch instructions Julien Grall
2016-06-07 16:06 ` [PATCH v3 09/16] xen/arm: Introduce alternative runtime patching Julien Grall
2016-06-07 17:24 ` Konrad Rzeszutek Wilk
2016-06-08 9:39 ` Julien Grall
2016-06-08 18:17 ` Konrad Rzeszutek Wilk
2016-06-08 18:22 ` Julien Grall
2016-06-08 18:35 ` Konrad Rzeszutek Wilk
2016-06-09 13:33 ` Julien Grall
2016-06-07 16:06 ` [PATCH v3 10/16] xen/arm: cpufeature: Provide an helper to check if a capability is supported Julien Grall
2016-06-22 9:59 ` Stefano Stabellini
2016-06-22 10:09 ` Julien Grall
2016-06-22 10:14 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 11/16] xen/arm: Detect silicon revision and set cap bits accordingly Julien Grall
2016-06-22 10:00 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 12/16] xen/arm: Document the errata implemented in Xen Julien Grall
2016-06-22 10:03 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 13/16] xen/arm: arm64: Add Cortex-A53 cache errata workaround Julien Grall
2016-06-22 10:04 ` Stefano Stabellini
2016-06-07 16:06 ` [PATCH v3 14/16] xen/arm: arm64: Add cortex-A57 erratum 832075 workaround Julien Grall
2016-06-22 10:10 ` Stefano Stabellini
2016-06-07 16:06 ` Julien Grall [this message]
2016-06-07 16:06 ` [PATCH v3 16/16] xen/arm: arm64: Document Cortex-A57 erratum 834220 Julien Grall
2016-06-14 12:15 ` Julien Grall
2016-06-22 10:08 ` Stefano Stabellini
2016-06-22 10:18 ` Julien Grall
2016-06-22 10:37 ` Stefano Stabellini
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