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| author | Andrew Waterman <andrew@sifive.com> | 2021-05-20 14:56:57 -0700 |
|---|---|---|
| committer | Andrew Waterman <andrew@sifive.com> | 2021-05-20 14:59:16 -0700 |
| commit | 35100d2d08d6e99b73f7e6788a14738ba86e0b63 (patch) | |
| tree | 90e9ae2f616201e6a40f5e4923dbf4295253d3d5 | |
| parent | 78696fcaacb62374d3f54678d9f4b64a4cc9de04 (diff) | |
| download | riscv-isa-manual-35100d2d08d6e99b73f7e6788a14738ba86e0b63.zip riscv-isa-manual-35100d2d08d6e99b73f7e6788a14738ba86e0b63.tar.gz riscv-isa-manual-35100d2d08d6e99b73f7e6788a14738ba86e0b63.tar.bz2 | |
Clarify need for HFENCE.GVMA after hgatp.MODE change
| -rw-r--r-- | src/hypervisor.tex | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/src/hypervisor.tex b/src/hypervisor.tex index 93e68fd..04a55f6 100644 --- a/src/hypervisor.tex +++ b/src/hypervisor.tex @@ -1845,6 +1845,11 @@ the guest-physical memory management of all virtual machines, or even a global fence for all memory-management data structures. \end{commentary} +If {\tt hgatp}.MODE is changed for a given VMID, an HFENCE.GVMA with +{\em rs1}={\tt x0} (and {\em rs2} set to either {\tt x0} or the VMID) must +be executed to order subsequent guest translations with the MODE +change---even if the old MODE or new MODE is Bare. + Attempts to execute HFENCE.VVMA or HFENCE.GVMA when V=1 cause a virtual instruction trap, while attempts to do the same in U-mode cause an illegal instruction trap. |