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* [hyperv] Do not steal ownership from the Gen 2 UEFI firmwareMichael Brown2017-07-281-0/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | We must not steal ownership from the Gen 2 UEFI firmware, since doing so will cause an immediate system crash (most likely in the form of a reboot). This problem was masked before commit a0f6e75 ("[hyperv] Do not fail if guest OS ID MSR is already set"), since prior to that commit we would always fail if we found any non-zero guest OS identity. We now accept a non-zero previous guest OS identity in order to allow for situations such as chainloading from iPXE to another iPXE, and as a prerequisite for commit b91cc98 ("[hyperv] Cope with Windows Server 2016 enlightenments"). A proper fix would be to reverse engineer the UEFI protocols exposed within the Hyper-V Gen 2 firmware and use these to bind to the VMBus device representing the network connection, (with the native Hyper-V driver moved to become a BIOS-only feature). As an interim solution, fail to initialise the native Hyper-V driver if we detect the guest OS identity known to be used by the Gen 2 UEFI firmware. This will cause the standard all-drivers build (ipxe.efi) to fall back to using the SNP driver. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [cpuid] Allow input %ecx value to be specifiedMichael Brown2017-06-161-5/+5
| | | | | | | | | | | | | | | | | | | | For some CPUID leaves (e.g. %eax=0x00000004), the result depends on the input value of %ecx. Allow this subfunction number to be specified as a parameter to the cpuid() wrapper. The subfunction number is exposed via the ${cpuid/...} settings mechanism using the syntax ${cpuid/<subfunction>.0x40.<register>.<function>} e.g. ${cpuid/0.0x40.0.0x0000000b} ${cpuid/1.0x40.0.0x0000000b} to retrieve the CPU topology information. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Cope with Windows Server 2016 enlightenmentsMichael Brown2017-04-281-10/+125
| | | | | | | | | | | | | | | | | | | | | | | An "enlightened" external bootloader (such as Windows Server 2016's winload.exe) may take ownership of the Hyper-V connection before all INT 13 operations have been completed. When this happens, all VMBus devices are implicitly closed and we are left with a non-functional network connection. Detect when our Hyper-V connection has been lost (by checking the SynIC message page MSR). Reclaim ownership of the Hyper-V connection and reestablish any VMBus devices, without disrupting any existing iPXE state (such as IPv4 settings attached to the network device). Windows Server 2016 will not cleanly take ownership of an active Hyper-V connection. Experimentation shows that we can quiesce by resetting only the SynIC message page MSR; this results in a successful SAN boot (on a Windows 2012 R2 physical host). Choose to quiesce by resetting (almost) all MSRs, in the hope that this will be more robust against corner cases such as a stray synthetic interrupt occurring during the handover. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Remove redundant return status code from mapping functionsMichael Brown2017-04-281-14/+4Star
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Do not fail if guest OS ID MSR is already setMichael Brown2017-04-261-2/+1Star
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Provide timer based on the 10MHz time reference count MSRMichael Brown2017-01-262-11/+108
| | | | | | | | | | | | | When running on AMD platforms, the legacy hardware emulation is extremely unreliable. In particular, the IRQ0 timer interrupt is likely to simply stop working, resulting in a total failure of any code that relies on timers (such as DHCP retransmission attempts). Work around this by using the 10MHz time counter provided by Hyper-V via an MSR. (This timer can be tested in KVM via the command-line option "-cpu host,hv_time".) Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [build] Fix the REQUIRE_SYMBOL mechanismMichael Brown2015-03-051-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | At some point in the past few years, binutils became more aggressive at removing unused symbols. To function as a symbol requirement, a relocation record must now be in a section marked with @progbits and must not be in a section which gets discarded during the link (either via --gc-sections or via /DISCARD/). Update REQUIRE_SYMBOL() to generate relocation records meeting these criteria. To minimise the impact upon the final binary size, we use existing symbols (specified via the REQUIRING_SYMBOL() macro) as the relocation targets where possible. We use R_386_NONE or R_X86_64_NONE relocation types to prevent any actual unwanted relocation taking place. Where no suitable symbol exists for REQUIRING_SYMBOL() (such as in config.c), the macro PROVIDE_REQUIRING_SYMBOL() can be used to generate a one-byte-long symbol to act as the relocation target. If there are versions of binutils for which this approach fails, then the fallback will probably involve killing off REQUEST_SYMBOL(), redefining REQUIRE_SYMBOL() to use the current definition of REQUEST_SYMBOL(), and postprocessing the linked ELF file with something along the lines of "nm -u | wc -l" to check that there are no undefined symbols remaining. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [legal] Relicense files under GPL2_OR_LATER_OR_UBDLMichael Brown2015-03-022-2/+6
| | | | | | | Relicense files for which I am the sole author (as identified by util/relicense.pl). Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Check for required featuresMichael Brown2015-02-202-0/+41
| | | | | | | | | | | Other hypervisors (e.g. KVM) may provide an unusable subset of the Hyper-V features, and our attempts to use these non-existent features cause the guest to reboot. Fix by explicitly checking for the Hyper-V features that we use. Reported-by: Ján ONDREJ (SAL) <ondrejj@salstar.sk> Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Add support for NetVSC paravirtual network devicesMichael Brown2014-12-181-0/+3
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Add support for VMBus devicesMichael Brown2014-12-181-0/+8
| | | | | | Add support for an abstraction of a VMBus device. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [hyperv] Add support for Hyper-V hypervisorMichael Brown2014-12-182-0/+595
Add support for detecting and communicating with the Hyper-V hypervisor. Signed-off-by: Michael Brown <mcb30@ipxe.org>