Re: [kvm-unit-tests PATCH 18/33] arm: realm: Add test for FPU/SIMD context save/restore

Andrew Jones
2024-05-10T15:28:51Z

On Fri, Apr 12, 2024 at 11:33:53AM GMT, Suzuki K Poulose wrote:
> From: Subhasish Ghosh <subhasish.ghosh@arm.com>
>
> Test that the FPU/SIMD registers are saved and restored correctly when
> context switching CPUs.
>
> In order to test fpu/simd functionality, we need to make sure that
> kvm-unit-tests doesn't generate code that uses the fpu registers, as that
> might interfere with the test results. Thus make sure we compile the tests
> with -mgeneral-regs-only.
>
> Signed-off-by: Subhasish Ghosh <subhasish.ghosh@arm.com>
> [ Added SVE register tests ]
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arm/Makefile.arm64 | 9 +
> arm/cstart64.S | 1 +
> arm/fpu.c | 424 ++++++++++++++++++++++++++++++++++++++
> arm/unittests.cfg | 8 +
> lib/arm64/asm/processor.h | 26 +++
> lib/arm64/asm/sysreg.h | 7 +
> 6 files changed, 475 insertions(+)
> create mode 100644 arm/fpu.c

When I build and run this test with EFI I get an SVE exception.

./configure --arch=arm64 --cross-prefix=aarch64-linux-gnu- --enable-efi --enable-efi-direct
qemu-system-aarch64 -nodefaults \
-machine virt -accel tcg -cpu max \
-display none -serial stdio \
-kernel arm/fpu.efi -append fpu.efi \
-bios /usr/share/edk2/aarch64/QEMU_EFI.silent.fd \
-smp 2 -machine acpi=off

UEFI firmware (version edk2-20230524-3.fc38 built at 00:00:00 on Jun 26 2023)
...

Address of image is: 0x43cfd000
PASS: fpu: FPU/SIMD register save/restore mask: 0xffffffff
PASS: fpu: FPU/SIMD register save/restore mask: 0xffffffff
Load address: 43cfd000
PC: 43d0b4e4 PC offset: e4e4
Unhandled exception ec=0x19 (SVE)
Vector: 4 (el1h_sync)
ESR_EL1: 66000000, ec=0x19 (SVE)
FAR_EL1: 0000000000000000 (not valid)
Exception frame registers:
pc : [<0000000043d0b4e4>] lr : [<0000000043d0b4d8>] pstate: 000002c5
sp : 0000000043d2bec0
x29: 0000000043d2bec0 x28: 0000000043d2bf58
x27: 0000000043d2bf60 x26: 0000000043d2bf68
x25: 0000000043d2bf70 x24: 8000000000000002
x23: 0000000043d2bf88 x22: 0000000000000000
x21: 000000004661b898 x20: 0000000043d2bfa8
x19: 0000000043d38e60 x18: 0000000000000000
x17: 00000000ffffa6ab x16: 0000000043d07780
x15: 0000000000000000 x14: 0000000000000010
x13: 0000000043d0d4b0 x12: 000000000000000f
x11: 0000000000000004 x10: 0000000000000066
x9 : 0000000000000066 x8 : 0000000043d3abf0
x7 : 0000000000000080 x6 : 0000000000000040
x5 : 0000000000003bce x4 : 0000000000043cfd
x3 : 0000000040101000 x2 : 0000000000040105
x1 : 0000000000000040 x0 : 1301001120110022

STACK: @e4e4 752c 1050

EXIT: STATUS=127

Thanks,
drew