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Thu, 10 Oct 2024 10:08:48 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 49BAD20075; Thu, 10 Oct 2024 10:08:48 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DFA812007A; Thu, 10 Oct 2024 10:08:47 +0000 (GMT) Received: from p-imbrenda (unknown [9.171.66.107]) by smtpav06.fra02v.mail.ibm.com (Postfix) with SMTP; Thu, 10 Oct 2024 10:08:47 +0000 (GMT) Date: Thu, 10 Oct 2024 12:08:35 +0200 From: Claudio Imbrenda To: Nico Boehr Cc: frankja@linux.ibm.com, thuth@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [kvm-unit-tests PATCH v4 2/2] s390x: add test for diag258 Message-ID: <20241010120835.363a1927@p-imbrenda> In-Reply-To: <20241010071228.565038-3-nrb@linux.ibm.com> References: <20241010071228.565038-1-nrb@linux.ibm.com> <20241010071228.565038-3-nrb@linux.ibm.com> Organization: IBM X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: tJDHg1J6UqWVpfOGtms7N1AVUa7bFrhM X-Proofpoint-GUID: 9V60ncwgQUi8wO4vMtu2n1Tzuq9wUHfm X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-10_07,2024-10-09_02,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 impostorscore=0 phishscore=0 priorityscore=1501 mlxlogscore=999 bulkscore=0 mlxscore=0 malwarescore=0 adultscore=0 spamscore=0 clxscore=1015 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2410100065 On Thu, 10 Oct 2024 09:11:52 +0200 Nico Boehr wrote: > This adds a test for diag258 (page ref service/async page fault). > > There recently was a virtual-real address confusion bug, so we should > test: > - diag258 parameter Rx is a real adress > - crossing the end of RAM with the parameter list yields an addressing > exception > - invalid diagcode in the parameter block yields an specification > exception > - diag258 correctly applies prefixing. > > Note that we're just testing error cases as of now. > > Signed-off-by: Nico Boehr Reviewed-by: Claudio Imbrenda > --- > s390x/Makefile | 1 + > s390x/diag258.c | 259 ++++++++++++++++++++++++++++++++++++++++++++ > s390x/unittests.cfg | 3 + > 3 files changed, 263 insertions(+) > create mode 100644 s390x/diag258.c > > diff --git a/s390x/Makefile b/s390x/Makefile > index 23342bd64f44..66d71351caab 100644 > --- a/s390x/Makefile > +++ b/s390x/Makefile > @@ -44,6 +44,7 @@ tests += $(TEST_DIR)/exittime.elf > tests += $(TEST_DIR)/ex.elf > tests += $(TEST_DIR)/topology.elf > tests += $(TEST_DIR)/sie-dat.elf > +tests += $(TEST_DIR)/diag258.elf > > pv-tests += $(TEST_DIR)/pv-diags.elf > pv-tests += $(TEST_DIR)/pv-icptcode.elf > diff --git a/s390x/diag258.c b/s390x/diag258.c > new file mode 100644 > index 000000000000..4746615bb944 > --- /dev/null > +++ b/s390x/diag258.c > @@ -0,0 +1,259 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Diag 258: Async Page Fault Handler > + * > + * Copyright (c) 2024 IBM Corp > + * > + * Authors: > + * Nico Boehr > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +static uint8_t prefix_buf[LC_SIZE] __attribute__((aligned(LC_SIZE))); > + > +#define __PF_RES_FIELD 0x8000000000000000UL > + > +/* copied from Linux arch/s390/mm/pfault.c */ > +struct pfault_refbk { > + u16 refdiagc; > + u16 reffcode; > + u16 refdwlen; > + u16 refversn; > + u64 refgaddr; > + u64 refselmk; > + u64 refcmpmk; > + u64 reserved; > +}; > + > +uint64_t pfault_token = 0x0123fadec0fe3210UL; > + > +static struct pfault_refbk pfault_init_refbk __attribute__((aligned(8))) = { > + .refdiagc = 0x258, > + .reffcode = 0, /* TOKEN */ > + .refdwlen = sizeof(struct pfault_refbk) / sizeof(uint64_t), > + .refversn = 2, > + .refgaddr = (u64)&pfault_token, > + .refselmk = 1UL << 48, > + .refcmpmk = 1UL << 48, > + .reserved = __PF_RES_FIELD > +}; > + > +static struct pfault_refbk pfault_cancel_refbk __attribute((aligned(8))) = { > + .refdiagc = 0x258, > + .reffcode = 1, /* CANCEL */ > + .refdwlen = sizeof(struct pfault_refbk) / sizeof(uint64_t), > + .refversn = 2, > + .refgaddr = 0, > + .refselmk = 0, > + .refcmpmk = 0, > + .reserved = 0 > +}; > + > +static inline int diag258(struct pfault_refbk *refbk) > +{ > + int rc = -1; > + > + asm volatile( > + " diag %[refbk],%[rc],0x258\n" > + : [rc] "+d" (rc) > + : [refbk] "a" (refbk), "m" (*(refbk)) > + : "cc"); > + return rc; > +} > + > +static void test_priv(void) > +{ > + report_prefix_push("privileged"); > + expect_pgm_int(); > + enter_pstate(); > + diag258(&pfault_init_refbk); > + check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION); > + report_prefix_pop(); > +} > + > +static void* page_map_outside_real_space(phys_addr_t page_real) > +{ > + pgd_t *root = (pgd_t *)(stctg(1) & PAGE_MASK); > + void* vaddr = alloc_vpage(); > + > + install_page(root, page_real, vaddr); > + > + return vaddr; > +} > + > +/* > + * Verify that the refbk pointer is a real address and not a virtual > + * address. This is tested by enabling DAT and establishing a mapping > + * for the refbk that is outside of the bounds of our (guest-)physical > + * address space. > + */ > +static void test_refbk_real(void) > +{ > + struct pfault_refbk *refbk; > + void *refbk_page; > + pgd_t *root; > + > + report_prefix_push("refbk is real"); > + > + /* Set up virtual memory and allocate a physical page for storing the refbk */ > + setup_vm(); > + refbk_page = alloc_page(); > + > + /* Map refblk page outside of physical memory identity mapping */ > + root = (pgd_t *)(stctg(1) & PAGE_MASK); > + refbk = page_map_outside_real_space(virt_to_pte_phys(root, refbk_page)); > + > + /* Assert the mapping really is outside identity mapping */ > + report_info("refbk is at 0x%lx", (u64)refbk); > + report_info("ram size is 0x%lx", get_ram_size()); > + assert((u64)refbk > get_ram_size()); > + > + /* Copy the init refbk to the page */ > + memcpy(refbk, &pfault_init_refbk, sizeof(struct pfault_refbk)); > + > + /* Protect the virtual mapping to avoid diag258 actually doing something */ > + protect_page(refbk, PAGE_ENTRY_I); > + > + expect_pgm_int(); > + diag258(refbk); > + check_pgm_int_code(PGM_INT_CODE_ADDRESSING); > + report_prefix_pop(); > + > + free_page(refbk_page); > + disable_dat(); > + irq_set_dat_mode(false, 0); > +} > + > +/* > + * Verify diag258 correctly applies prefixing. > + */ > +static void test_refbk_prefixing(void) > +{ > + const size_t lowcore_offset_for_refbk = offsetof(struct lowcore, pad_0x03a0); > + struct pfault_refbk *refbk_in_prefix, *refbk_in_reverse_prefix; > + uint32_t old_prefix; > + uint64_t ry; > + > + report_prefix_push("refbk prefixing"); > + > + report_info("refbk at lowcore offset 0x%lx", lowcore_offset_for_refbk); > + > + assert((unsigned long)&prefix_buf < SZ_2G); > + > + memcpy(prefix_buf, 0, LC_SIZE); > + > + /* > + * After the call to set_prefix() below, this will refer to absolute > + * address lowcore_offset_for_refbk (reverse prefixing). > + */ > + refbk_in_reverse_prefix = (struct pfault_refbk *)(&prefix_buf[0] + lowcore_offset_for_refbk); > + > + /* > + * After the call to set_prefix() below, this will refer to absolute > + * address &prefix_buf[0] + lowcore_offset_for_refbk (forward prefixing). > + */ > + refbk_in_prefix = (struct pfault_refbk *)OPAQUE_PTR(lowcore_offset_for_refbk); > + > + old_prefix = get_prefix(); > + set_prefix((uint32_t)(uintptr_t)prefix_buf); > + > + /* > + * If diag258 would not be applying prefixing on access to > + * refbk_in_reverse_prefix correctly, it would access absolute address > + * refbk_in_reverse_prefix (which to us is accessible at real address > + * refbk_in_prefix). > + * Make sure it really fails by putting invalid function code > + * at refbk_in_prefix. > + */ > + refbk_in_prefix->refdiagc = 0xc0fe; > + > + /* > + * Put a valid refbk at refbk_in_reverse_prefix. > + */ > + memcpy(refbk_in_reverse_prefix, &pfault_init_refbk, sizeof(pfault_init_refbk)); > + > + ry = diag258(refbk_in_reverse_prefix); > + report(!ry, "real address refbk accessed"); > + > + /* > + * Activating should have worked. Cancel the activation and expect > + * return 0. If activation would not have worked, this should return with > + * 4 (pfault handshaking not active). > + */ > + ry = diag258(&pfault_cancel_refbk); > + report(!ry, "handshaking canceled"); > + > + set_prefix(old_prefix); > + > + report_prefix_pop(); > +} > + > +/* > + * Verify that a refbk exceeding physical memory is not accepted, even > + * when crossing a frame boundary. > + */ > +static void test_refbk_crossing(void) > +{ > + const size_t bytes_in_last_page = 8; > + struct pfault_refbk *refbk = (struct pfault_refbk *)(get_ram_size() - bytes_in_last_page); > + > + report_prefix_push("refbk crossing"); > + > + report_info("refbk is at 0x%lx", (u64)refbk); > + report_info("ram size is 0x%lx", get_ram_size()); > + assert(sizeof(struct pfault_refbk) > bytes_in_last_page); > + > + /* Copy bytes_in_last_page bytes of the init refbk to the page */ > + memcpy(refbk, &pfault_init_refbk, bytes_in_last_page); > + > + expect_pgm_int(); > + diag258(refbk); > + check_pgm_int_code(PGM_INT_CODE_ADDRESSING); > + report_prefix_pop(); > +} > + > +/* > + * Verify that a refbk with an invalid refdiagc is not accepted. > + */ > +static void test_refbk_invalid_diagcode(void) > +{ > + struct pfault_refbk refbk __attribute__((aligned(8))) = pfault_init_refbk; > + > + report_prefix_push("invalid refdiagc"); > + refbk.refdiagc = 0xc0fe; > + > + expect_pgm_int(); > + diag258(&refbk); > + check_pgm_int_code(PGM_INT_CODE_SPECIFICATION); > + report_prefix_pop(); > +} > + > +int main(void) > +{ > + report_prefix_push("diag258"); > + > + expect_pgm_int(); > + diag258((struct pfault_refbk *)0xfffffffffffffff0); > + if (clear_pgm_int() == PGM_INT_CODE_SPECIFICATION) { > + report_skip("diag258 not supported"); > + } else { > + test_priv(); > + /* Other tests rely on invalid diagcodes doing nothing */ > + test_refbk_invalid_diagcode(); > + test_refbk_real(); > + test_refbk_prefixing(); > + test_refbk_crossing(); > + } > + > + report_prefix_pop(); > + return report_summary(); > +} > diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg > index 3a9decc932f2..8131ba105d3f 100644 > --- a/s390x/unittests.cfg > +++ b/s390x/unittests.cfg > @@ -392,3 +392,6 @@ file = sie-dat.elf > > [pv-attest] > file = pv-attest.elf > + > +[diag258] > +file = diag258.elf