Re: [Qemu-devel] [PATCH v3 11/13] tests: acpi: add simple arm/virt testcase

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 26 Apr 2019 17:28:10 +0100
Wei Xu <xuwei5@hisilicon.com> wrote:

> Hi Igor,
> 
> On 4/26/2019 12:54 PM, Igor Mammedov wrote:
> > On Fri, 26 Apr 2019 00:51:56 +0800
> > x00249684 <xuwei5@huawei.com> wrote:
> > 
> >> Hi Igor,
> >>
> >> +static void test_acpi_virt_tcg(void)
> >> +{
> >> +    test_data data = {
> >> +        .machine = "virt",
> >> +        .uefi_fl1 = "pc-bios/edk2-aarch64-code.fd",
> >> +        .uefi_fl2 = "pc-bios/edk2-arm-vars.fd",
> >> +        .cd = "tests/data/uefi-boot-images/bios-tables-test.aarch64.iso.qcow2",
> >> +        .ram_start = 0x40000000ULL,
> >> +        .scan_len = 128ULL * 1024 * 1024,
> >> +    };
> >> +
> >> +    test_acpi_one("-cpu cortex-a57 ", &data);
> >>
> >> Replaced the cortex-a57 with host and succesfully tested on the hisilicon arm64 
> >> D05 board. Otherwise it failed with "kvm_init_vcpu failed: Invalid argument".
> >> Is it possilbe to set the cpu type like numa-test.c?
> > 
> > I think it works with numa-test because it uses TCG only but in case of bios-tables-test
> > it uses accel="kvm:tcg" to leverage KVM capabilities whenever possible to speed up test.
> > 
> > Now back to our ARM test case, uefi requirement is to use 64bit CPU (hence it was cortex-a57)
> > however unlike x86 it obviously breaks since KVM accelerator on ARM host is used
> > and it doesn't work with anything other than 'host' cpu model.
> > 
> > I think we still want to use KVM whenever possible, but problem lies in that
> > user (testcase) doesn't have an idea if KVM accelerator is available and host is 64 CPU.
> > 
> > to sum up we need to support 2 modes:
> >   1. host is 64 ARM, use kvm with -cpu host
> >   2. all other cases use tcg with -cpu cortex-a57
> > 
> > I can hack to probe if /dev/kvm is accessible and host is 64 bit and use #1
> > otherwise fallback to #2
> > or as quick fix do only #2 initially and think about a better solution to #1 
> 
> Thanks!
> Fine to me.
> 
> > 
> > Is there any other suggestions/opinions how to approach issue/proceed.
> 
> To check the host cpu architecture is ARM or not, maybe we can check the value
> of "CPU implementer" is 0x41 or not from the /proc/cpuinfo.

it turned out it's more complicated.
we also should pick a correct GIC depending on host's CPU and that
changes ACPI tables, so it will worn on some hosts and fail on other.

I'll add a patch to enable test case to pick accelerator and force TCG
for ARM tests for now.

> 
> Best Regards,
> Wei
> 
> > 
> > PS:
> > we probably would like to reuse this not only for acpi tests but also for other
> > arm/virt test cases that involve running guest code. 
> > 
> >> Thanks!
> >>
> >> Best Regards,
> >> Wei
> > 
> > 
> > .
> > 
>