x86_64: fix crashes when the guest switches CPU mode - #336
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I ran into a triple fault while trying to boot Linux with with Limine on top of OVMF and this was the cause. Signed-off-by: Bill Nguyen <bill.nguyen@unsw.edu.au>
On x86, software exit long mode by clearing CR0.PG. However, the act of clearing this bit causes side effects in the processor that we the VMM must emulate in software. Otherwise vmresume will fail with invalid guest state. I ran into this problem while trying Limine on OVMF. Which seems to drop into protected mode from long mode when booting Linux. Signed-off-by: Bill Nguyen <bill.nguyen@unsw.edu.au>
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Fixed a few crashes I ran into while trying out desktop Linux distros on libvmm with OVMF. See the commits for more details.