On 11/23/21 4:07 PM, Stefano Stabellini wrote:
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx> 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 all bits set as an invalid value. 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@xxxxxxxxxxxxxxx Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
Applied to for-linus-5.16c -boris
