Messages in this thread | | | Subject | Re: [PATCH] arm/xen: Enable user access to the kernel before issuing a privcmd call | From | Ian Campbell <> | Date | Fri, 11 Sep 2015 15:29:20 +0100 |
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On Fri, 2015-09-11 at 15:16 +0100, Julien Grall wrote: > When Xen is copyin data to/from the guest it will check if the kernel
"copying"
> has the right to do the access. If not, the hypercall will return an > error. > > After the commit a5e090acbf545c0a3b04080f8a488b17ec41fe02 "ARM: > software-based priviledged-no-access support", the kernel can't access
"privileged"
> anymore the user space by default. This will result to fail on every
"any more" (or "any longer")
> hypercall made by the userspace (i.e via privcmd). > > We have to enable the userspace access and then restore the correct > permission everytime the privmcd is used to made an hypercall.
"every time" and "privcmd"
> HYPERCALL1(tmem_op); > HYPERCALL2(multicall); > > -ENTRY(privcmd_call) > +ENTRY(__privcmd_call)
arch/arm/include/asm/assembler.h seems to contain uaccess_* macros which could be used right here directly I think? That would be preferable to wrapping I think.
Ian.
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