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Diffstat (limited to 'results/classifier/118/kernel/664')
| -rw-r--r-- | results/classifier/118/kernel/664 | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/results/classifier/118/kernel/664 b/results/classifier/118/kernel/664 new file mode 100644 index 000000000..00295498e --- /dev/null +++ b/results/classifier/118/kernel/664 @@ -0,0 +1,44 @@ +kernel: 0.917 +x86: 0.916 +architecture: 0.851 +device: 0.790 +graphic: 0.737 +performance: 0.731 +mistranslation: 0.722 +vnc: 0.678 +socket: 0.655 +network: 0.641 +ppc: 0.636 +PID: 0.583 +semantic: 0.561 +peripherals: 0.560 +boot: 0.533 +VMM: 0.531 +register: 0.516 +files: 0.507 +hypervisor: 0.506 +KVM: 0.489 +permissions: 0.486 +virtual: 0.465 +i386: 0.465 +risc-v: 0.463 +debug: 0.424 +arm: 0.410 +TCG: 0.385 +user-level: 0.321 +assembly: 0.277 + +hvf-accelerated x86_64 incorrectly reports virtual address bit width via CPUID +Description of problem: +When running qemu-system-x86_64 with hvf acceleration enabled the maximum extended cpuid function (available via EAX=0x80000000) is reported to be 0x80000001, which means that physical address and virtual address bit width (which is supposed to be reported via EAX=0x80000008) is not available. As per the intel IA32/64 manual: `Processors that do not support CPUID function 80000008H, support a linear-address width of 32.`, while in actuality qemu-system-x86_64 with hvf acceleration supports virtual addresses of up to 48 bit in width, like most modern x86_64 processors. +Steps to reproduce: +This can be observed when running SerenityOS on x86_64 qemu with hvf acceleration based on the following dmesg lines: +``` +[Kernel]: CPU[0]: Physical address bit width: 36 +[Kernel]: CPU[0]: Virtual address bit width: 32 +``` +But can also be reproduced by running the CPUID instruction with EAX set to 0x80000000 and observing that the returned value is 0x80000001. +Additional information: +The best way to resolve this as far as I can tell is to expose the 0x80000008 CPUID function and report the real values. + +NOTE: This is a report of the underlying bug that was found during the investigation of an issue raised in the SerenityOS repository, see https://github.com/SerenityOS/serenity/issues/10382 for more information. |