Re: [kvm-unit-tests PATCH 3/3] s390x: Ultavisor guest API test

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Fri, 17 Jul 2020 10:58:13 -0400
Janosch Frank <frankja@linux.ibm.com> wrote:

> Test the error conditions of guest 2 Ultravisor calls, namely:
>      * Query Ultravisor information
>      * Set shared access
>      * Remove shared access
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>  lib/s390x/asm/uv.h  |  68 +++++++++++++++++++
>  s390x/Makefile      |   1 +
>  s390x/unittests.cfg |   3 +
>  s390x/uv-guest.c    | 156
> ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 228
> insertions(+) create mode 100644 lib/s390x/asm/uv.h
>  create mode 100644 s390x/uv-guest.c
> 
> diff --git a/lib/s390x/asm/uv.h b/lib/s390x/asm/uv.h
> new file mode 100644
> index 0000000..14ab5cc
> --- /dev/null
> +++ b/lib/s390x/asm/uv.h
> @@ -0,0 +1,68 @@
> +/*
> + * s390x Ultravisor related definitions
> + *
> + * Copyright (c) 2020 IBM Corp
> + *
> + * Authors:
> + *  Janosch Frank <frankja@linux.ibm.com>
> + *
> + * This code is free software; you can redistribute it and/or modify
> it
> + * under the terms of the GNU General Public License version 2.
> + */
> +#ifndef UV_H
> +#define UV_H
> +
> +#define UVC_RC_EXECUTED		0x0001
> +#define UVC_RC_INV_CMD		0x0002
> +#define UVC_RC_INV_STATE	0x0003
> +#define UVC_RC_INV_LEN		0x0005
> +#define UVC_RC_NO_RESUME	0x0007
> +
> +#define UVC_CMD_QUI			0x0001
> +#define UVC_CMD_SET_SHARED_ACCESS	0x1000
> +#define UVC_CMD_REMOVE_SHARED_ACCESS	0x1001
> +
> +/* Bits in installed uv calls */
> +enum uv_cmds_inst {
> +	BIT_UVC_CMD_QUI = 0,
> +	BIT_UVC_CMD_SET_SHARED_ACCESS = 8,
> +	BIT_UVC_CMD_REMOVE_SHARED_ACCESS = 9,
> +};
> +
> +struct uv_cb_header {
> +	u16 len;
> +	u16 cmd;	/* Command Code */
> +	u16 rc;		/* Response Code */
> +	u16 rrc;	/* Return Reason Code */
> +} __attribute__((packed))  __attribute__((aligned(8)));
> +
> +struct uv_cb_qui {
> +	struct uv_cb_header header;
> +	u64 reserved08;
> +	u64 inst_calls_list[4];
> +	u64 reserved30[15];
> +} __attribute__((packed))  __attribute__((aligned(8)));
> +
> +struct uv_cb_share {
> +	struct uv_cb_header header;
> +	u64 reserved08[3];
> +	u64 paddr;
> +	u64 reserved28;
> +} __attribute__((packed))  __attribute__((aligned(8)));
> +
> +static inline int uv_call(unsigned long r1, unsigned long r2)
> +{
> +	int cc;
> +
> +	asm volatile(
> +		"0:	.insn rrf,0xB9A40000,%[r1],%[r2],0,0\n"
> +		"		brc	3,0b\n"
> +		"		ipm	%[cc]\n"
> +		"		srl	%[cc],28\n"
> +		: [cc] "=d" (cc)
> +		: [r1] "a" (r1), [r2] "a" (r2)
> +		: "memory", "cc");
> +	return cc;
> +}
> +
> +#endif
> diff --git a/s390x/Makefile b/s390x/Makefile
> index 0f54bf4..c2213ad 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -18,6 +18,7 @@ tests += $(TEST_DIR)/skrf.elf
>  tests += $(TEST_DIR)/smp.elf
>  tests += $(TEST_DIR)/sclp.elf
>  tests += $(TEST_DIR)/css.elf
> +tests += $(TEST_DIR)/uv-guest.elf
>  tests_binary = $(patsubst %.elf,%.bin,$(tests))
>  
>  all: directories test_cases test_cases_binary
> diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
> index b35269b..38c3257 100644
> --- a/s390x/unittests.cfg
> +++ b/s390x/unittests.cfg
> @@ -92,3 +92,6 @@ extra_params = -device virtio-net-ccw
>  [skrf]
>  file = skrf.elf
>  smp = 2
> +
> +[uv-guest]
> +file = uv-guest.elf
> \ No newline at end of file
> diff --git a/s390x/uv-guest.c b/s390x/uv-guest.c
> new file mode 100644
> index 0000000..0cb5fae
> --- /dev/null
> +++ b/s390x/uv-guest.c
> @@ -0,0 +1,156 @@
> +/*
> + * Guest Ultravisor Call tests
> + *
> + * Copyright (c) 2020 IBM Corp
> + *
> + * Authors:
> + *  Janosch Frank <frankja@linux.ibm.com>
> + *
> + * This code is free software; you can redistribute it and/or modify
> it
> + * under the terms of the GNU General Public License version 2.
> + */
> +
> +#include <libcflat.h>
> +#include <alloc_page.h>
> +#include <asm/page.h>
> +#include <asm/asm-offsets.h>
> +#include <asm/interrupt.h>
> +#include <asm/facility.h>
> +#include <asm/uv.h>
> +
> +static inline int share(unsigned long addr, u16 cmd)
> +{
> +	struct uv_cb_share uvcb = {
> +		.header.cmd = cmd,
> +		.header.len = sizeof(uvcb),
> +		.paddr = addr
> +	};
> +
> +	uv_call(0, (u64)&uvcb);
> +	return uvcb.header.rc;
> +}
> +
> +static inline int uv_set_shared(unsigned long addr)
> +{
> +	return share(addr, UVC_CMD_SET_SHARED_ACCESS);
> +}
> +
> +static inline int uv_remove_shared(unsigned long addr)
> +{
> +	return share(addr, UVC_CMD_REMOVE_SHARED_ACCESS);
> +}
> +
> +static void test_priv(void)
> +{
> +	struct uv_cb_header uvcb = {};
> +
> +	report_prefix_push("privileged");
> +
> +	report_prefix_push("query");
> +	expect_pgm_int();
> +	uvcb.cmd = UVC_CMD_QUI;
> +	uvcb.len = sizeof(struct uv_cb_qui);
> +	enter_pstate();
> +	uv_call(0, (u64)&uvcb);
> +	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
> +	report_prefix_pop();
> +
> +	report_prefix_push("share");
> +	expect_pgm_int();
> +	enter_pstate();
> +	uv_set_shared(0x42000);
> +	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
> +	report_prefix_pop();
> +
> +	report_prefix_push("unshare");
> +	expect_pgm_int();
> +	enter_pstate();
> +	uv_remove_shared(0x42000);

I don't like using a hardwired address here (and above). Things can get
messy if the address ends up outside memory or overlapping code.

I think the best approach would be to declare a page aligned buffer and
use that (or even allocate a page) 

> +	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
> +	report_prefix_pop();
> +
> +	report_prefix_pop();
> +}
> +
> +static void test_query(void)
> +{
> +	struct uv_cb_qui uvcb = {
> +		.header.cmd = UVC_CMD_QUI,
> +		.header.len = sizeof(uvcb) - 8,
> +	};
> +
> +	report_prefix_push("query");
> +	uv_call(0, (u64)&uvcb);
> +	report(uvcb.header.rc == UVC_RC_INV_LEN, "length");
> +
> +	uvcb.header.len = sizeof(uvcb);
> +	uv_call(0, (u64)&uvcb);
> +	report(uvcb.header.rc == UVC_RC_EXECUTED, "successful
> query"); +
> +	/*
> +	 * These bits have been introduced with the very first
> +	 * Ultravisor version and are expected to always be available
> +	 * because they are basic building blocks.
> +	 */
> +	report(uvcb.inst_calls_list[0] & (1UL << (63 -
> BIT_UVC_CMD_QUI)),
> +	       "query indicated");
> +	report(uvcb.inst_calls_list[0] & (1UL << (63 -
> BIT_UVC_CMD_SET_SHARED_ACCESS)),
> +	       "share indicated");
> +	report(uvcb.inst_calls_list[0] & (1UL << (63 -
> BIT_UVC_CMD_REMOVE_SHARED_ACCESS)),
> +	       "unshare indicated");
> +	report_prefix_pop();
> +}
> +
> +static void test_sharing(void)
> +{
> +	unsigned long mem = (unsigned long)alloc_page();
> +	struct uv_cb_share uvcb = {
> +		.header.cmd = UVC_CMD_SET_SHARED_ACCESS,
> +		.header.len = sizeof(uvcb) - 8,
> +	};
> +
> +	report_prefix_push("share");
> +	uv_call(0, (u64)&uvcb);
> +	report(uvcb.header.rc == UVC_RC_INV_LEN, "length");
> +	report(uv_set_shared(mem) == UVC_RC_EXECUTED, "share");
> +	report_prefix_pop();
> +
> +	report_prefix_push("unshare");
> +	uvcb.header.cmd = UVC_CMD_REMOVE_SHARED_ACCESS;
> +	uv_call(0, (u64)&uvcb);
> +	report(uvcb.header.rc == UVC_RC_INV_LEN, "length");
> +	report(uv_remove_shared(mem) == UVC_RC_EXECUTED, "unshare");
> +	free_page((void *)mem);
> +	report_prefix_pop();
> +
> +	report_prefix_pop();
> +}
> +
> +static void test_invalid(void)
> +{
> +	struct uv_cb_header uvcb = {
> +		.len = 16,
> +		.cmd = 0x4242,
> +	};
> +
> +	uv_call(0, (u64)&uvcb);
> +	report(uvcb.rc == UVC_RC_INV_CMD, "invalid command");
> +}
> +
> +int main(void)
> +{
> +	bool has_uvc = test_facility(158);
> +
> +	report_prefix_push("uvc");
> +	if (!has_uvc) {
> +		report_skip("Ultravisor call facility is not
> available");
> +		goto done;
> +	}
> +
> +	test_priv();
> +	test_invalid();
> +	test_query();
> +	test_sharing();
> +done:
> +	return report_summary();
> +}

once the above comment is addressed:
Claudio Imbrenda <imbrenda@linux.ibm.com>