On 21/08/2020 12:19, Laszlo Ersek wrote:
On 08/19/20 20:46, Michael Brown wrote:
FWIW, iPXE's equivalent logic (based on a combination of what the PXE
spec says and what the Intel reference PXE implementation actually does,
which is not necessarily the same thing) is to *ignore* PXE_BOOT_SERVERS
if a DHCP filename is available and option 43 tag 6 bit 3 is *set*.
Sorry, I expressed my concern incorrectly (I think I was tripped up by
the typo in Maciej's commit message).
My fault; I should have read more closely.
It's about bit#2 in PXE_DISCOVERY_CONTROL.
The question is whether bit#2 is *equivalent* to adhering to
PXE_BOOT_SERVERS ("if, and only if").
When bit#2 is set, the spec says we must. OK.
When bit#2 is clear, the spec doesn't say anything. So two
interpretations are possible, "we still may consider PXE_BOOT_SERVERS",
and "we must not consider PXE_BOOT_SERVERS".
iPXE's interpretation is:
- if bit 2 is set then the subsequent boot server discovery will ignore
replies from any servers not mentioned (for the selected boot server
type) in PXE_BOOT_SERVERS
- if bit 2 is clear then the subsequent boot server discovery will
accept replies from any server
This seems consistent with the spec paragraph stating:
"If PXE_DISCOVERY_CONTROL bit 2 is set, the client may still use
multicast and broadcast discovery (if it is permitted by bits 0
and 1); but the client may only accept replies from servers that
are identified in the PXE_BOOT_SERVERS option."
Anyway -- I'm sending this just to explain my earlier email. My main
point remains:
11640b08-6f42-e4d8-356d-91d4bdf86c2c@redhat.com">http://mid.mail-archive.com/11640b08-6f42-e4d8-356d-91d4bdf86c2c@redhat.com
(alt link: https://edk2.groups.io/g/devel/message/64530)
Resolving as INVALID seems appropriate to me.
Thanks,
Michael
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