Messages in this thread | | | Date | Fri, 19 Nov 2021 17:32:15 -0500 | Subject | Re: [PATCH v2] xen: detect uninitialized xenbus in xenbus_init | From | Boris Ostrovsky <> |
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On 11/19/21 3:29 PM, Stefano Stabellini wrote: > From: Stefano Stabellini <stefano.stabellini@xilinx.com> > > If the xenstore page hasn't been allocated properly, reading the value > of the related hvm_param (HVM_PARAM_STORE_PFN) won't actually return > error. Instead, it will succeed and return zero. Instead of attempting > to xen_remap a bad guest physical address, detect this condition and > return early. > > Note that although a guest physical address of zero for > HVM_PARAM_STORE_PFN is theoretically possible, it is not a good choice > and zero has never been validly used in that capacity. > > Also recognize the invalid value of INVALID_PFN which is ULLONG_MAX. > > For 32-bit Linux, any pfn above ULONG_MAX would get truncated. Pfns > above ULONG_MAX should never be passed by the Xen tools to HVM guests > anyway, so check for this condition and return early. > > Cc: stable@vger.kernel.org > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
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