6f5a960678
Currently EPT TLB invalidation is done by incrementing a generation counter and issuing an IPI to all CPUs currently running vCPU threads. The VMM inner loop caches the most recently observed generation on each host CPU and invalidates TLB entries before executing the VM if the cached generation number is not the most recent value. pmap_invalidate_ept() issues IPIs to force each vCPU to stop executing guest instructions and reload the generation number. However, it does not actually wait for vCPUs to exit, potentially creating a window where guests may continue to reference stale TLB entries. Fix the problem by bracketing guest execution with an SMR read section which is entered before loading the invalidation generation. Then, pmap_invalidate_ept() increments the current write sequence before loading pm_active and sending IPIs, and polls readers to ensure that all vCPUs potentially operating with stale TLB entries have exited before pmap_invalidate_ept() returns. Also ensure that unsynchronized loads of the generation counter are wrapped with atomic(9), and stop (inconsistently) updating the invalidation counter and pm_active bitmask with acquire semantics. Reviewed by: grehan, kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D26910 |
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| .. | ||
| ept.c | ||
| ept.h | ||
| vmcs.c | ||
| vmcs.h | ||
| vmx_controls.h | ||
| vmx_cpufunc.h | ||
| vmx_genassym.c | ||
| vmx_msr.c | ||
| vmx_msr.h | ||
| vmx_support.S | ||
| vmx.c | ||
| vmx.h | ||
| vtd.c | ||