mirror of https://github.com/xemu-project/xemu.git
1d7e6318af
The DPDES support for doorbell emulation and handling for KVM on PAPR
guests was added in Linux via [1]. Subsequently, a new GSB (Guest State
Buffer) element for DPDES was added in Linux; the same has been missing
in TCG L0 implementation. Add support for DPDES register's APIv2 GSB
element and required handling in `spapr_nested.c`.
Currently, booting a KVM guest inside a QEMU TCG guest fails with the
following crash. The crash occurs while handling the GUEST_RUN_VCPU
hcall made in TCG L0. In the hcall handling path, map_and_getset_state()
calls getset_state(), which, in turn, calls guest_state_request_check()
to validate the GSR (Guest State Request) elements. During this process,
guest_state_request_check() iterates over the GSR elements and receives
a NULL return code from guest_state_element_type_find() for the type
variable corresponding to the DPDES register's elemetn ID (which was
unknown to TCG L0). Subsequently, getset_state() returns H_P3,
ultimately leading to the hcall failure and causing the KVM guest to
crash.
KVM: unknown exit, hardware reason ffffffffffffffea
[ ... KVM register dump ... ]
Fix this by adding the required support in TCG L0 implementation of
APIv2.
[1] https://lore.kernel.org/all/20240605113913.83715-1-gautam@linux.ibm.com/
Fixes:
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||
|---|---|---|
| .. | ||
| authz | ||
| block | ||
| chardev | ||
| crypto | ||
| disas | ||
| exec | ||
| fpu | ||
| gdbstub | ||
| hw | ||
| io | ||
| libdecnumber | ||
| migration | ||
| monitor | ||
| net | ||
| qapi | ||
| qemu | ||
| qom | ||
| scsi | ||
| semihosting | ||
| standard-headers | ||
| sysemu | ||
| tcg | ||
| ui | ||
| user | ||
| elf.h | ||
| glib-compat.h | ||
| qemu-io.h | ||
| qemu-main.h | ||