From: zhichao.huang@linaro.org (Zhichao Huang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 01/15] KVM: arm: plug guest debug exploit
Date: Tue, 29 Sep 2015 13:13:01 +0800 [thread overview]
Message-ID: <560A1DDD.1060100@linaro.org> (raw)
In-Reply-To: <20150902113804.GJ10991@cbox>
On 2015/9/2 19:38, Christoffer Dall wrote:
>
> I really think that we should read the register, clear the bits you care
> about (MDBGen and HDBGen) and then write back the register.
>
> So, if I recall correctly, this is to avoid having to set HDCR_TDE
> below?
>
> Given Will's concerns about touching this register, I'm thinking if we
> shouldn't start with the HDCR_TDE enabled (and a handler in KVM) and
> then see if we want to add this optimization later?
>
> At the very least, you should do as Will pointed out and predicate
> writes to this register based on whether the reset code in
> hw_breakpoint.c successfully reset the debug regs. I think checking the
> debug_err_mask variable from the C code and pass this on to the Hyp code
> would be the right way to go.
>
> But as I said, I think we should just trap debug exceptions to begin
> with (to plug the hole) and then add the more intelligent stuff later.
>
OK, I will set HDCR_TDE, and ignore all the debug exceptions in
KVM handlers to prevent the guest to mess with the host states.
>> + .endif
>> +
>> + mcr p14, 0, r2, c0, c2, 2 @ DBGDSCR
>> .endm
>>
>> /*
>> @@ -620,7 +633,7 @@ ARM_BE8(rev r6, r6 )
>> * (hardware reset value is 0) */
>> .macro set_hdcr operation
>> mrc p15, 4, r2, c1, c1, 1
>> - ldr r3, =(HDCR_TPM|HDCR_TPMCR)
>> + ldr r3, =(HDCR_TPM|HDCR_TPMCR|HDCR_TDRA|HDCR_TDOSA|HDCR_TDA)
>
>
>
>> .if \operation == vmentry
>> orr r2, r2, r3 @ Trap some perfmon accesses
>> .else
>> --
>> 1.7.12.4
>>
>
> Thanks,
> -Christoffer
>
next prev parent reply other threads:[~2015-09-29 5:13 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-10 13:25 [PATCH v4 00/15] KVM: arm: debug infrastructure support Zhichao Huang
2015-08-10 13:25 ` [PATCH v4 01/15] KVM: arm: plug guest debug exploit Zhichao Huang
2015-09-02 11:38 ` Christoffer Dall
2015-09-29 5:13 ` Zhichao Huang [this message]
2015-08-10 13:25 ` [PATCH v4 02/15] KVM: arm: rename pm_fake handler to trap_raz_wi Zhichao Huang
2015-08-10 13:25 ` [PATCH v4 03/15] KVM: arm: enable to use the ARM_DSCR_MDBGEN macro from KVM assembly code Zhichao Huang
2015-08-10 13:25 ` [PATCH v4 04/15] KVM: arm: common infrastructure for handling AArch32 CP14/CP15 Zhichao Huang
2015-09-02 13:09 ` Christoffer Dall
2015-08-10 13:25 ` [PATCH v4 05/15] KVM: arm: check ordering of all system register tables Zhichao Huang
2015-08-10 13:25 ` [PATCH v4 06/15] KVM: arm: add trap handlers for 32-bit debug registers Zhichao Huang
2015-09-02 16:03 ` Christoffer Dall
2015-08-10 13:25 ` [PATCH v4 07/15] KVM: arm: add trap handlers for 64-bit " Zhichao Huang
2015-08-10 13:26 ` [PATCH v4 08/15] KVM: arm: add a trace event for cp14 traps Zhichao Huang
2015-08-10 13:26 ` [PATCH v4 09/15] KVM: arm: redefine kvm_cpu_context_t to save the host cp14 states Zhichao Huang
2015-09-02 14:54 ` Christoffer Dall
2015-08-10 13:26 ` [PATCH v4 10/15] KVM: arm: implement world switch for debug registers Zhichao Huang
2015-09-02 14:53 ` Christoffer Dall
2015-09-29 5:32 ` Zhichao Huang
2015-09-29 7:34 ` Christoffer Dall
2015-08-10 13:26 ` [PATCH v4 11/15] KVM: arm: add a function to keep track of host use of the " Zhichao Huang
2015-09-02 15:40 ` Christoffer Dall
2015-08-10 13:26 ` [PATCH v4 12/15] KVM: arm: " Zhichao Huang
2015-09-02 15:44 ` Christoffer Dall
2015-08-10 13:26 ` [PATCH v4 13/15] KVM: arm: keep track of guest " Zhichao Huang
2015-09-02 16:01 ` Christoffer Dall
2015-09-29 5:36 ` Zhichao Huang
2015-08-10 13:26 ` [PATCH v4 14/15] KVM: arm: implement lazy world switch for " Zhichao Huang
2015-09-02 16:06 ` Christoffer Dall
2015-08-10 13:26 ` [PATCH v4 15/15] KVM: arm: enable trapping of all " Zhichao Huang
2015-09-02 16:08 ` Christoffer Dall
2015-09-29 5:41 ` Zhichao Huang
2015-09-29 7:38 ` Christoffer Dall
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