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bh=I4h7vyx8d98MGbRX6SH6EZkNtqsv47ZRB8QWMoS6Bts=; b=aVztQq6gxGalwxGtt/qYZTBv8yl8HdC1tFfRvaOvZ557bUOJgvDZAP0e2l23ZxE6FXFNjA 9MgAMynjnlul/dFxuJZxqf4vugiRBvrJgIOjiUnyDZqNOJ7Dg6Iag/4yponm4tHt2YIhxY iERtqzC8ZP7sJm5wteUprR5LRYZDlhE= X-MC-Unique: hAGTyLvDOj-3i5KL5O_Swg-1 From: marcandre.lureau@redhat.com To: qemu-devel@nongnu.org Cc: Richard Henderson , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Bin Meng , Daniel Henrique Barboza , qemu-ppc@nongnu.org, qemu-s390x@nongnu.org, Alistair Francis , qemu-riscv@nongnu.org, Peter Maydell , viktor.prutyanov@redhat.com, Greg Kurz , frankja@linux.ibm.com, David Hildenbrand , Palmer Dabbelt , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , David Gibson , qemu-arm@nongnu.org, Cornelia Huck , Thomas Huth Subject: [PULL 10/10] dump: fix kdump to work over non-aligned blocks Date: Thu, 6 Oct 2022 19:34:29 +0400 Message-Id: <20221006153430.2775580-11-marcandre.lureau@redhat.com> In-Reply-To: <20221006153430.2775580-1-marcandre.lureau@redhat.com> References: <20221006153430.2775580-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=marcandre.lureau@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1665076346913100001 From: Marc-Andr=C3=A9 Lureau Rewrite get_next_page() to work over non-aligned blocks. When it encounters non aligned addresses, it will try to fill a page provided by the caller. This solves a kdump crash with "tpm-crb-cmd" RAM memory region, qemu-kvm: ../dump/dump.c:1162: _Bool get_next_page(GuestPhysBlock **, uint64_t *, uint8_t **, DumpState *): Assertion `(block->target_start & ~target_page_mask) =3D=3D 0' failed. because: guest_phys_block_add_section: target_start=3D00000000fed40080 target_end=3D= 00000000fed41000: added (count: 4) Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=3D2120480 Signed-off-by: Marc-Andr=C3=A9 Lureau Acked-by: David Hildenbrand --- dump/dump.c | 79 +++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 56 insertions(+), 23 deletions(-) diff --git a/dump/dump.c b/dump/dump.c index b55a497c42..236559b03a 100644 --- a/dump/dump.c +++ b/dump/dump.c @@ -1116,50 +1116,81 @@ static uint64_t dump_pfn_to_paddr(DumpState *s, uin= t64_t pfn) } =20 /* - * exam every page and return the page frame number and the address of the= page. - * bufptr can be NULL. note: the blocks here is supposed to reflect guest-= phys - * blocks, so block->target_start and block->target_end should be interal - * multiples of the target page size. + * Return the page frame number and the page content in *bufptr. bufptr ca= n be + * NULL. If not NULL, *bufptr must contains a target page size of pre-allo= cated + * memory. This is not necessarily the memory returned. */ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr, uint8_t **bufptr, DumpState *s) { GuestPhysBlock *block =3D *blockptr; - hwaddr addr, target_page_mask =3D ~((hwaddr)s->dump_info.page_size - 1= ); - uint8_t *buf; + uint32_t page_size =3D s->dump_info.page_size; + uint8_t *buf =3D NULL, *hbuf; + hwaddr addr; =20 /* block =3D=3D NULL means the start of the iteration */ if (!block) { block =3D QTAILQ_FIRST(&s->guest_phys_blocks.head); *blockptr =3D block; addr =3D block->target_start; + *pfnptr =3D dump_paddr_to_pfn(s, addr); } else { - addr =3D dump_pfn_to_paddr(s, *pfnptr + 1); + *pfnptr +=3D 1; + addr =3D dump_pfn_to_paddr(s, *pfnptr); } assert(block !=3D NULL); =20 - if ((addr >=3D block->target_start) && - (addr + s->dump_info.page_size <=3D block->target_end)) { - buf =3D block->host_addr + (addr - block->target_start); - } else { - /* the next page is in the next block */ - block =3D QTAILQ_NEXT(block, next); - *blockptr =3D block; - if (!block) { - return false; + while (1) { + if (addr >=3D block->target_start && addr < block->target_end) { + size_t n =3D MIN(block->target_end - addr, page_size - addr % = page_size); + hbuf =3D block->host_addr + (addr - block->target_start); + if (!buf) { + if (n =3D=3D page_size) { + /* this is a whole target page, go for it */ + assert(addr % page_size =3D=3D 0); + buf =3D hbuf; + break; + } else if (bufptr) { + assert(*bufptr); + buf =3D *bufptr; + memset(buf, 0, page_size); + } else { + return true; + } + } + + memcpy(buf + addr % page_size, hbuf, n); + addr +=3D n; + if (addr % page_size =3D=3D 0) { + /* we filled up the page */ + break; + } + } else { + /* the next page is in the next block */ + *blockptr =3D block =3D QTAILQ_NEXT(block, next); + if (!block) { + break; + } + + addr =3D block->target_start; + /* are we still in the same page? */ + if (dump_paddr_to_pfn(s, addr) !=3D *pfnptr) { + if (buf) { + /* no, but we already filled something earlier, return= it */ + break; + } else { + /* else continue from there */ + *pfnptr =3D dump_paddr_to_pfn(s, addr); + } + } } - addr =3D block->target_start; - buf =3D block->host_addr; } =20 - assert((block->target_start & ~target_page_mask) =3D=3D 0); - assert((block->target_end & ~target_page_mask) =3D=3D 0); - *pfnptr =3D dump_paddr_to_pfn(s, addr); if (bufptr) { *bufptr =3D buf; } =20 - return true; + return buf !=3D NULL; } =20 static void write_dump_bitmap(DumpState *s, Error **errp) @@ -1297,6 +1328,7 @@ static void write_dump_pages(DumpState *s, Error **er= rp) uint8_t *buf; GuestPhysBlock *block_iter =3D NULL; uint64_t pfn_iter; + g_autofree uint8_t *page =3D NULL; =20 /* get offset of page_desc and page_data in dump file */ offset_desc =3D s->offset_page; @@ -1332,12 +1364,13 @@ static void write_dump_pages(DumpState *s, Error **= errp) } =20 offset_data +=3D s->dump_info.page_size; + page =3D g_malloc(s->dump_info.page_size); =20 /* * dump memory to vmcore page by page. zero page will all be resided i= n the * first page of page section */ - while (get_next_page(&block_iter, &pfn_iter, &buf, s)) { + for (buf =3D page; get_next_page(&block_iter, &pfn_iter, &buf, s); buf= =3D page) { /* check zero page */ if (buffer_is_zero(buf, s->dump_info.page_size)) { ret =3D write_cache(&page_desc, &pd_zero, sizeof(PageDescripto= r), --=20 2.37.3