Re: [kvm-unit-tests PATCH v3 0/5] arm/arm64: Add support for running under kvmtool

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On Mon, Feb 04, 2019 at 01:44:07PM +0000, Alexandru Elisei wrote:
> kvm-unit-tests is designed to be run with QEMU as the virtual machine
> monitor. It relies on devices emulated by QEMU (like isa-debug-exit or
> testdev) and it makes certain assumptions based on the implicit QEMU
> virtual environment configuration (like the serial base address).
> 
> kvmtool [1] is a lightweight virtual machine monitor for running KVM
> guests. kvmtool has reduced complexity compared to QEMU and is easily
> hackable.
> 
> This patch series aims to make it possible to run kvm-unit-tests using
> kvmtool on the arm and arm64 architectures, with two caveats:
> 
> (1) When terminating a test, the userspace process won't exit with an exit
> code that signals the success or failure of the test. Output from the test
> can still be parsed to determine the outcome of the test.
> 
> (2) kvmtool has been designed to work with a linux guest and it
> automatically generates the command line arguments for a Linux kernel. The
> arm/arm64 selftest and gic tests will fail if unexpected command line
> arguments are found. To get around this limitation, the test binary needs
> to be loaded using the --firmware option introduced by kvmtool in commit
> 5e4b563d75b9 ("arm: Allow command line for firmware"). This option
> suppresses the automatic kernel command line and can be used to run all
> tests, not just the tests that require specific arguments.
> 
> The run scripts haven't been modified. To run a test under kvmtool, one
> needs to launch kvmtool manually. For example, to run the timer test the
> following command can be used:
> 
> lkvm run --cpus 1 --console serial --firmware timer.flat.
> 
> To run the gicv3-ipi test:
> 
> lkvm run --cpus 8 --console serial --params "ipi" --irqchip gicv3 \
>     --firmware gic.flat

This looks good to me. I tested with lkvm and saw that all tests were able
to run and pass, except pci-test since lkvm doesn't have pci-testdev. The
only other issue was selftest.vectors-user which ends in user mode and
thus can't make the PSCI call to exit. The following patch can get that
to work if lkvm users want it

diff --git a/arm/selftest.c b/arm/selftest.c
index ea5101ef7217..7ba3f02a9b9d 100644
--- a/arm/selftest.c
+++ b/arm/selftest.c
@@ -272,10 +272,18 @@ static bool check_svc(void)
 }
 #endif
 
+static void user_psci_off(struct pt_regs *regs, unsigned int esr)
+{
+       psci_system_off();
+       halt();
+}
+
 static void check_vectors(void *arg __unused)
 {
        report("und", check_und());
        report("svc", check_svc());
+       if (is_user())
+               install_exception_handler(EL0_SYNC_64, ESR_EL1_EC_UNKNOWN, user_psci_off);
        exit(report_summary());
 }


Anyway, thanks for submitting these patches to enable another user of
kvm-unit-tests.

drew


> 
> Changes in v3:
> * Updated cover letter with information about the kvmtool --firmware
>   option.
> * Gathered Reviewed-by tags.
> * Renamed the config.h define UART_EARLY_BASE to CONFIG_UART_EARLY_BASE and
>   made the necessary casts in lib/arm/io.c
> 
> Changes in v2:
> * Generate lib/config.h when configuring kvm-unit-tests; arm/arm64 uses it
>   to get the UART address.
> * Added --vmm configure option for arm/arm64 which will set the UART
>   address in lib/config.h when the tests are run under QEMU or kvmtool.
> * Renamed psci_sys_reset() to psci_system_reset().
> * Dropped patches that allowed a test to ignore unexpected command line
>   arguments.
> 
> Summary:
> * Patches 1, 2 and 3 add support for configuring kvm-unit-tests on arm and
>   arm64 to use the ns16550a UART emulated by kvmtool.
> * Patches 4 and 5 provide an alternative mechanism for terminating the
>   virtual machine by using PSCI.
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/kvmtool.git/
> [2] https://www.spinics.net/lists/kvm-arm/msg34352.html
> 
> Alexandru Elisei (5):
>   lib: arm: Use UART address from generated config.h
>   configure: arm/arm64: Add --vmm option with no effect
>   lib: arm: Use ns16550a UART when --vmm=kvmtool
>   lib: arm: Implement PSCI SYSTEM_OFF in psci_system_off()
>   lib: arm: Fallback to psci_system_off() in exit()
> 
>  configure          | 32 ++++++++++++++++++++++++++++++++
>  Makefile           |  2 +-
>  lib/arm/asm/psci.h |  3 ++-
>  lib/arm/io.c       | 41 ++++++++++++++++++++++++++---------------
>  lib/arm/psci.c     |  8 +++++++-
>  .gitignore         |  1 +
>  6 files changed, 69 insertions(+), 18 deletions(-)
> 
> -- 
> 2.17.0
> 



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