[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0
From: |
Claudio Fontana |
Subject: |
[Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0 |
Date: |
Mon, 2 Jun 2014 18:16:12 +0200 |
Hello Peter,
I am porting OSv to AArch64, and I have some working code running on
the Foundation Models,
where I run qemu natively with --enable-kvm,
which does not seem to work when run instead on top of the system emulation.
In particular I get a sync exception when I try to msr to TTBR0_EL1.
The ESR as read in env->cp15.esr_el[1] is 0x8400000e, which looking up
in the ESR table means
Instruction fault, with IFSC (instruction fault status code) = 0xe,
which should match
0b0011LL = permission fault (LL indicates level at which fault occurred).
with LL = 0b10 meaning EL2.
The code is in particular:
00000000401db2d0 <mmu::switch_to_runtime_page_tables()>:
401db2d0: d00037a0 adrp x0, 408d1000 <unique_mtx+0x10>
401db2d4: 9130e000 add x0, x0, #0xc38
401db2d8: f9400000 ldr x0, [x0]
401db2dc: 92748c00 and x0, x0, #0xfffffffff000
401db2e0: d5182000 msr ttbr0_el1, x0
401db2e4: d5033fdf isb
401db2e8: d00037a0 adrp x0, 408d1000 <unique_mtx+0x10>
401db2ec: 9130e000 add x0, x0, #0xc38
401db2f0: f9400400 ldr x0, [x0,#8]
401db2f4: 92748c00 and x0, x0, #0xfffffffff000
401db2f8: d5182020 msr ttbr1_el1, x0
401db2fc: d5033fdf isb
401db300: d5033f9f dsb sy
401db304: d508831f tlbi vmalle1is
401db308: d5033f9f dsb sy
401db30c: d5033fdf isb
401db310: d65f03c0 ret
ELR_EL1 in env->elr_el[1] reads as 0x401da200, which is strangely
enough the address of the first instruction of the exception vector
entry for sync:
...
401da200: 14000169 b 401da7a4 <entry_sync>
401da204: d503201f nop
...
401da280: 14000174 b 401da850 <entry_irq>
401da284: d503201f nop
The source is available at:
https://github.com/cloudius-systems/osv/blob/master/arch/aarch64/mmu.cc
Thanks for any advice,
Claudio
- [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0,
Claudio Fontana <=
- Re: [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0, Claudio Fontana, 2014/06/02
- Re: [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0, Peter Maydell, 2014/06/02
- Re: [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0, Claudio Fontana, 2014/06/03
- Re: [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0, Ian Campbell, 2014/06/08
- Re: [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0, Peter Maydell, 2014/06/08
- Re: [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0, Ian Campbell, 2014/06/08
- Re: [Qemu-devel] AArch64 QEMU System emulation: issue with TTBR0, Ian Campbell, 2014/06/08
- [Qemu-devel] [PATCH] target-arm: A64: Correct handling of UXN bit., Ian Campbell, 2014/06/08
- Re: [Qemu-devel] [PATCH] target-arm: A64: Correct handling of UXN bit., Peter Maydell, 2014/06/09