Although with the patches in QEMU/Kernel that can restrict the OS to run with sv39/sv48 only, and the fact that there are not enough real hardware board supporting above sv48, I don’t know whether there will be sufficient motivation to fix the problem in the short term.Īlso worth noting until very recently (Intel implemented 5-level paging around the release of Ice Lake), x86_64 has been staying 48 bits a for long time.īut I think openjdk as a application, it should not has any limitation on virtual address length,Įven if it has very close relationship with hardware, just as qemu should not depend on hardware VM size, it's none of business for an application, because all other apps can run very well. I agree that it would be nice to support different modes. This has been discussed in a previous thread. On Wed, at 9:33 AM Vladimir Kempik wrote:ĭisable sv57 csr and rebuild qemu - put 0 hereĢ3 нояб. Especially given the current discussions in RISC-V on reducing the cost of auipc/jalr, movptr, and trampolines.
#CAT PROC CPUINFO VIRTUAL ADDRESS FULL#
I wouldn't want to pay the full cost of sv57 or sv64 while no existing boards or hardware even support anything more than sv48. The solution on the OpenJDK should IMO to probe at startup for the satp mode (sv39/sv48/sv57/sv64) and generate the appropriate and cheapest movptr according to this value. I'll keep you posted as soon as I've anything material to share.
We are currently working on contributing to Qemu a command-line option to disable/enable certain modes in Qemu.
Subject: Re: openjdk 20 crash on linux kernel 5.19, because it can not support huge VM? I see this kind of information is availble on linux-riscv64 at /proc/cpuinfo:Ĭc: "Zixian Cai", " riscv-port-dev at ", "Ze Zhang" That would be better and more elegant than simply crashing the JVM afterwards. I think at this stage we should do some detection for sv57+ at JVM startup time and explicitly issue a warning and stop early. Subject: Re: Re: openjdk 20 crash on linux kernel 5.19, because it can not support huge VM? # jdk-satp/bin/java -versionįrom:riscv-port-dev On Behalf Of yangfei at iscas.ac.cnĬc: Vladimir Kempik Zixian Cai riscv-port-dev at Ze Zhang OpenJDK 64-Bit Server VM OpenJDK (build 20, mixed mode) OpenJDK Runtime Environment OpenJDK (build 20) $ /riscv-qemu/bin/qemu-riscv64 -L ~/riscv-sysroot/ release/images/jdk/bin/java -version QEMU-USER will return empty string when reading /proc/cpuinfo. Turns out we can only get mmu info on QEMU-SYSTEM and hardware. Hardware (HiFive Unmatched) by reading /proc/cpuinfo. I’m trying to get satp mode on QEMU-USER, QEMU-SYSTEM and Subject: RE: Re: openjdk 20 crash on linux kernel 5.19, because it can not support huge VM? To: " yangfei at iscas.ac.cn", "Ludovic Henry" Ĭc: "Vladimir Kempik", "Zixian Cai", " riscv-port-dev at ", "Ze Zhang" I guess qemu-user doesn't provide /proc/cpuinfo for us to use like qemu-system.īut it's still nice if we can enable that detection in qemu-system mode or on real hardware platforms.
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