Initial NV support #6460
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Initial NV support #6460
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This patch lays the groundwork for nested virtualization by rearranging
the KVM guest's memory map.
Key changes include:
- Introducing a dedicated per-VCPU memory region for L2 VMs.
- Updating `executor/kvm.h` with:
- Adjusted stack addresses for the L1 guest.
- Detailed memory layout macros for L2 VM structures
Set up the L1 guest's 64-bit Task State Segment (TSS), a prerequisite for VMX/SVM.
Add vendor-specific code to turn on nested virtualization on Intel and AMD. Also provide get_cpu_vendor() to pick the correct implementation.
Provide basic setup for registers, page tables, and segments to create Intel/AMD-based nested virtual machines. Note that the machines do not get started yet.
Now that we are using volatiles in guest_main(), there is no particular need to base the numbers on primes (this didn't work well with Clang anyway). Instead, group the commands logically and leave some space between the groups for future updates.
The new command loads an instruction blob into the specified L2 VM.
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Provide a SYZOS API command to launch the L2 VM using the VMLAUNCH (Intel) or VMRUN (AMD) instruction. For testing purposes, each L2->L1 exit is followed by a guest_uexit_l2() returning the exit code to L0. Common exit reasons (like HLT) will be mapped into a common exit code space (0xe2e20000 | reason), so that a single test can be used for both Intel and AMD. Vendor-specific exit codes will be returned using the 0xe2110000 mask for Intel and 0xe2aa0000 for AMD.
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dvyukov
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Nov 19, 2025
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Some test seeds would be useful to ensure it's working and keeps working.
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Thanks! I do have some, will send them separately. |
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