Re: [kvm-unit-tests v2 07/10] powerpc/spapr_vpa: Add basic VPA tests

[Thomas Huth <thuth@redhat.com>]

On 20/03/2023 08.03, Nicholas Piggin wrote:
> The VPA is a(n optional) memory structure shared between the hypervisor
> and operating system, defined by PAPR. This test defines the structure
> and adds registration, deregistration, and a few simple sanity tests.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>   lib/linux/compiler.h    |  2 +
>   lib/powerpc/asm/hcall.h |  1 +
>   lib/ppc64/asm/vpa.h     | 62 ++++++++++++++++++++++++++++
>   powerpc/Makefile.ppc64  |  2 +-
>   powerpc/spapr_vpa.c     | 90 +++++++++++++++++++++++++++++++++++++++++

Please add the new test to powerpc/unittests.cfg, otherwise it won't get 
picked up by the run_tests.sh script.

> diff --git a/lib/linux/compiler.h b/lib/linux/compiler.h
> index 6f565e4..c9d205e 100644
> --- a/lib/linux/compiler.h
> +++ b/lib/linux/compiler.h
> @@ -45,7 +45,9 @@
>   
>   #define barrier()	asm volatile("" : : : "memory")
>   
> +#ifndef __always_inline
>   #define __always_inline	inline __attribute__((always_inline))
> +#endif

What's this change good for? ... it doesn't seem to be related to this patch?

> diff --git a/lib/ppc64/asm/vpa.h b/lib/ppc64/asm/vpa.h
> new file mode 100644
> index 0000000..11dde01
> --- /dev/null
> +++ b/lib/ppc64/asm/vpa.h
> @@ -0,0 +1,62 @@
> +#ifndef _ASMPOWERPC_VPA_H_
> +#define _ASMPOWERPC_VPA_H_
> +/*
> + * This work is licensed under the terms of the GNU LGPL, version 2.
> + */
> +
> +#ifndef __ASSEMBLY__
> +
> +struct vpa {
> +	uint32_t	descriptor;
> +	uint16_t	size;
> +	uint8_t		reserved1[3];
> +	uint8_t		status;

Where does this status field come from? ... My LoPAPR only says that there 
are 18 "reserved" bytes in total here.

> +	uint8_t		reserved2[14];
> +	uint32_t	fru_node_id;
> +	uint32_t	fru_proc_id;
> +	uint8_t		reserved3[56];
> +	uint8_t		vhpn_change_counters[8];
> +	uint8_t		reserved4[80];
> +	uint8_t		cede_latency;
> +	uint8_t		maintain_ebb;
> +	uint8_t		reserved5[6];
> +	uint8_t		dtl_enable_mask;
> +	uint8_t		dedicated_cpu_donate;
> +	uint8_t		maintain_fpr;
> +	uint8_t		maintain_pmc;
> +	uint8_t		reserved6[28];
> +	uint64_t	idle_estimate_purr;
> +	uint8_t		reserved7[28];
> +	uint16_t	maintain_nr_slb;
> +	uint8_t		idle;
> +	uint8_t		maintain_vmx;
> +	uint32_t	vp_dispatch_count;
> +	uint32_t	vp_dispatch_dispersion;
> +	uint64_t	vp_fault_count;
> +	uint64_t	vp_fault_tb;
> +	uint64_t	purr_exprop_idle;
> +	uint64_t	spurr_exprop_idle;
> +	uint64_t	purr_exprop_busy;
> +	uint64_t	spurr_exprop_busy;
> +	uint64_t	purr_donate_idle;
> +	uint64_t	spurr_donate_idle;
> +	uint64_t	purr_donate_busy;
> +	uint64_t	spurr_donate_busy;
> +	uint64_t	vp_wait3_tb;
> +	uint64_t	vp_wait2_tb;
> +	uint64_t	vp_wait1_tb;
> +	uint64_t	purr_exprop_adjunct_busy;
> +	uint64_t	spurr_exprop_adjunct_busy;

The above two fields are also marked as "reserved" in my LoPAPR ... which 
version did you use?

> +	uint32_t	supervisor_pagein_count;
> +	uint8_t		reserved8[4];
> +	uint64_t	purr_exprop_adjunct_idle;
> +	uint64_t	spurr_exprop_adjunct_idle;
> +	uint64_t	adjunct_insns_executed;

dito for the above three lines... I guess my LoPAPR is too old...

> +	uint8_t		reserved9[120];
> +	uint64_t	dtl_index;
> +	uint8_t		reserved10[96];
> +};
> +
> +#endif /* __ASSEMBLY__ */
> +
> +#endif /* _ASMPOWERPC_VPA_H_ */
> diff --git a/powerpc/Makefile.ppc64 b/powerpc/Makefile.ppc64
> index ea68447..b0ed2b1 100644
> --- a/powerpc/Makefile.ppc64
> +++ b/powerpc/Makefile.ppc64
> @@ -19,7 +19,7 @@ reloc.o  = $(TEST_DIR)/reloc64.o
>   OBJDIRS += lib/ppc64
>   
>   # ppc64 specific tests
> -tests =
> +tests = $(TEST_DIR)/spapr_vpa.elf
>   
>   include $(SRCDIR)/$(TEST_DIR)/Makefile.common
>   
> diff --git a/powerpc/spapr_vpa.c b/powerpc/spapr_vpa.c
> new file mode 100644
> index 0000000..45688fe
> --- /dev/null
> +++ b/powerpc/spapr_vpa.c
> @@ -0,0 +1,90 @@
> +/*
> + * Test sPAPR hypervisor calls (aka. h-calls)

Adjust to "Test sPAPR H_REGISTER_VPA hypervisor call" ?

> + * This work is licensed under the terms of the GNU LGPL, version 2.
> + */
> +#include <libfdt/libfdt.h>
> +#include <devicetree.h>
> +#include <libcflat.h>
> +#include <util.h>
> +#include <alloc.h>
> +#include <asm/processor.h>
> +#include <asm/hcall.h>
> +#include <asm/vpa.h>
> +#include <asm/io.h> /* for endian accessors */
> +
> +static void print_vpa(struct vpa *vpa)
> +{
> +	printf("VPA\n");
> +	printf("descriptor:			0x%08x\n", be32_to_cpu(vpa->descriptor));
> +	printf("size:				    0x%04x\n", be16_to_cpu(vpa->size));
> +	printf("status:				      0x%02x\n", vpa->status);
> +	printf("fru_node_id:			0x%08x\n", be32_to_cpu(vpa->fru_node_id));
> +	printf("fru_proc_id:			0x%08x\n", be32_to_cpu(vpa->fru_proc_id));
> +	printf("vhpn_change_counters:		0x%02x %02x %02x %02x %02x %02x %02x %02x\n", vpa->vhpn_change_counters[0], vpa->vhpn_change_counters[1], vpa->vhpn_change_counters[2], vpa->vhpn_change_counters[3], vpa->vhpn_change_counters[4], vpa->vhpn_change_counters[5], vpa->vhpn_change_counters[6], vpa->vhpn_change_counters[7]);
> +	printf("vp_dispatch_count:		0x%08x\n", be32_to_cpu(vpa->vp_dispatch_count));
> +	printf("vp_dispatch_dispersion:		0x%08x\n", be32_to_cpu(vpa->vp_dispatch_dispersion));
> +	printf("vp_fault_count:			0x%08lx\n", be64_to_cpu(vpa->vp_fault_count));
> +	printf("vp_fault_tb:			0x%08lx\n", be64_to_cpu(vpa->vp_fault_tb));
> +	printf("purr_exprop_idle:		0x%08lx\n", be64_to_cpu(vpa->purr_exprop_idle));
> +	printf("spurr_exprop_idle:		0x%08lx\n", be64_to_cpu(vpa->spurr_exprop_idle));
> +	printf("purr_exprop_busy:		0x%08lx\n", be64_to_cpu(vpa->purr_exprop_busy));
> +	printf("spurr_exprop_busy:		0x%08lx\n", be64_to_cpu(vpa->spurr_exprop_busy));
> +	printf("purr_donate_idle:		0x%08lx\n", be64_to_cpu(vpa->purr_donate_idle));
> +	printf("spurr_donate_idle:		0x%08lx\n", be64_to_cpu(vpa->spurr_donate_idle));
> +	printf("purr_donate_busy:		0x%08lx\n", be64_to_cpu(vpa->purr_donate_busy));
> +	printf("spurr_donate_busy:		0x%08lx\n", be64_to_cpu(vpa->spurr_donate_busy));
> +	printf("vp_wait3_tb:			0x%08lx\n", be64_to_cpu(vpa->vp_wait3_tb));
> +	printf("vp_wait2_tb:			0x%08lx\n", be64_to_cpu(vpa->vp_wait2_tb));
> +	printf("vp_wait1_tb:			0x%08lx\n", be64_to_cpu(vpa->vp_wait1_tb));
> +	printf("purr_exprop_adjunct_busy:	0x%08lx\n", be64_to_cpu(vpa->purr_exprop_adjunct_busy));
> +	printf("spurr_exprop_adjunct_busy:	0x%08lx\n", be64_to_cpu(vpa->spurr_exprop_adjunct_busy));
> +	printf("purr_exprop_adjunct_idle:	0x%08lx\n", be64_to_cpu(vpa->purr_exprop_adjunct_idle));
> +	printf("spurr_exprop_adjunct_idle:	0x%08lx\n", be64_to_cpu(vpa->spurr_exprop_adjunct_idle));
> +	printf("adjunct_insns_executed:		0x%08lx\n", be64_to_cpu(vpa->adjunct_insns_executed));
> +	printf("dtl_index:			0x%08lx\n", be64_to_cpu(vpa->dtl_index));
> +}
> +
> +/**
> + * Test the H_REGISTER_VPA h-call register/deregister.
> + */
> +static void register_vpa(struct vpa *vpa)
> +{
> +	uint32_t cpuid = fdt_boot_cpuid_phys(dt_fdt());
> +	int disp_count1, disp_count2;
> +	int rc;
> +
> +	rc = hcall(H_REGISTER_VPA, 1ULL << 45, cpuid, vpa);
> +	report(rc == H_SUCCESS, "VPA registered");
> +
> +	print_vpa(vpa);
> +
> +	disp_count1 = be32_to_cpu(vpa->vp_dispatch_count);
> +	report(disp_count1 % 2 == 0, "Dispatch count is even while running");
> +	msleep(100);
> +	disp_count2 = be32_to_cpu(vpa->vp_dispatch_count);
> +	report(disp_count1 != disp_count2, "Dispatch count increments over H_CEDE");
> +
> +	rc = hcall(H_REGISTER_VPA, 5ULL << 45, cpuid, vpa);
> +	report(rc == H_SUCCESS, "VPA deregistered");
> +
> +	disp_count1 = be32_to_cpu(vpa->vp_dispatch_count);
> +	report(disp_count1 % 2 == 1, "Dispatch count is odd after deregister");
> +}

Now that was a very tame amount of tests ;-)

I'd suggest to add some more:

- Check hcall(H_REGISTER_VPA, 0, ...);
- Check hcall(H_REGISTER_VPA, ..., bad-cpu-id, ...)
- Check hcall(H_REGISTER_VPA, ..., ..., unaligned-address)
- Check hcall(H_REGISTER_VPA, ..., ..., illegal-address)
- Check registration with vpa->size being too small
- Check registration where the vpa crosses the 4k boundary

What do you think?

> +int main(int argc, char **argv)
> +{
> +	struct vpa *vpa;
> +
> +	vpa = memalign(4096, sizeof(*vpa));
> +
> +	memset(vpa, 0, sizeof(*vpa));
> +
> +	vpa->size = cpu_to_be16(sizeof(*vpa));
> +
> +	report_prefix_push("vpa");

This lacks the corresponding report_prefix_pop() later.

> +	register_vpa(vpa);
> +
> +	return report_summary();
> +}

  Thomas