From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52446) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eFKJJ-0005mD-Aw for qemu-devel@nongnu.org; Thu, 16 Nov 2017 08:34:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eFKJF-0005Bf-2d for qemu-devel@nongnu.org; Thu, 16 Nov 2017 08:34:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56778) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eFKJE-00059s-QF for qemu-devel@nongnu.org; Thu, 16 Nov 2017 08:34:25 -0500 Date: Thu, 16 Nov 2017 08:34:23 -0500 (EST) From: =?utf-8?Q?Marc-Andr=C3=A9?= Lureau Message-ID: <183118826.40770917.1510839263526.JavaMail.zimbra@redhat.com> In-Reply-To: <20171116035606-mutt-send-email-mst@kernel.org> References: <20171113192958.22953-1-marcandre.lureau@redhat.com> <20171113192958.22953-6-marcandre.lureau@redhat.com> <20171116035606-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v6 5/5] fw_cfg: write vmcoreinfo details List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, somlo@cmu.edu, qemu-devel@nongnu.org Hi ----- Original Message ----- > On Mon, Nov 13, 2017 at 08:29:58PM +0100, Marc-Andr=C3=A9 Lureau wrote: > > If the "etc/vmcoreinfo" fw_cfg file is present and we are not running > > the kdump kernel, write the addr/size of the vmcoreinfo ELF note. > >=20 > > Signed-off-by: Marc-Andr=C3=A9 Lureau > > Reviewed-by: Gabriel Somlo > > --- > > drivers/firmware/qemu_fw_cfg.c | 87 > > +++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 86 insertions(+), 1 deletion(-) > >=20 > > diff --git a/drivers/firmware/qemu_fw_cfg.c > > b/drivers/firmware/qemu_fw_cfg.c > > index 2ac4cd869fe6..7a70e7a549f6 100644 > > --- a/drivers/firmware/qemu_fw_cfg.c > > +++ b/drivers/firmware/qemu_fw_cfg.c > > @@ -35,6 +35,8 @@ > > #include > > #include > > #include > > +#include > > +#include > > =20 > > MODULE_AUTHOR("Gabriel L. Somlo "); > > MODULE_DESCRIPTION("QEMU fw_cfg sysfs support"); > > @@ -59,6 +61,8 @@ MODULE_LICENSE("GPL"); > > /* fw_cfg "file name" is up to 56 characters (including terminating nu= l) > > */ > > #define FW_CFG_MAX_FILE_PATH 56 > > =20 > > +#define VMCOREINFO_FORMAT_ELF 0x1 > > + > > /* platform device for dma mapping */ > > static struct device *dev; > > =20 > > @@ -127,7 +131,8 @@ static ssize_t fw_cfg_dma_transfer(void *address, u= 32 > > length, u32 control) > > =09dma_addr_t dma; > > =09ssize_t ret =3D length; > > =09enum dma_data_direction dir =3D > > -=09=09(control & FW_CFG_DMA_CTL_READ ? DMA_FROM_DEVICE : 0); > > +=09=09(control & FW_CFG_DMA_CTL_READ ? DMA_FROM_DEVICE : 0) | > > +=09=09(control & FW_CFG_DMA_CTL_WRITE ? DMA_TO_DEVICE : 0); > > =20 > > =09if (address && length) { > > =09=09dma_addr =3D dma_map_single(dev, address, length, dir); > > @@ -225,6 +230,48 @@ static ssize_t fw_cfg_read_blob(u16 key, > > =09return ret; > > } > > =20 > > +#ifdef CONFIG_CRASH_CORE > > +/* write chunk of given fw_cfg blob (caller responsible for sanity-che= ck) > > */ > > +static ssize_t fw_cfg_write_blob(u16 key, > > +=09=09=09=09 void *buf, loff_t pos, size_t count) > > +{ > > +=09u32 glk =3D -1U; > > +=09acpi_status status; > > +=09ssize_t ret =3D count; > > + > > +=09/* If we have ACPI, ensure mutual exclusion against any potential > > +=09 * device access by the firmware, e.g. via AML methods: > > +=09 */ > > +=09status =3D acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); > > +=09if (ACPI_FAILURE(status) && status !=3D AE_NOT_CONFIGURED) { > > +=09=09/* Should never get here */ > > +=09=09WARN(1, "%s: Failed to lock ACPI!\n", __func__); > > +=09=09memset(buf, 0, count); > > +=09=09return -EINVAL; > > +=09} > > + > > +=09mutex_lock(&fw_cfg_dev_lock); > > +=09if (pos =3D=3D 0) { > > +=09=09ret =3D fw_cfg_dma_transfer(buf, count, key << 16 > > +=09=09=09=09=09 | FW_CFG_DMA_CTL_SELECT > > +=09=09=09=09=09 | FW_CFG_DMA_CTL_WRITE); > > +=09} else { > > +=09=09iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl); > > +=09=09ret =3D fw_cfg_dma_transfer(NULL, pos, FW_CFG_DMA_CTL_SKIP); > > +=09=09if (ret < 0) > > +=09=09=09goto end; > > +=09=09ret =3D fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE); > > +=09} > > + > > +end: > > +=09mutex_unlock(&fw_cfg_dev_lock); > > + > > +=09acpi_release_global_lock(glk); > > + > > +=09return ret; > > +} > > +#endif /* CONFIG_CRASH_CORE */ > > + > > /* clean up fw_cfg device i/o */ > > static void fw_cfg_io_cleanup(void) > > { > > @@ -343,6 +390,37 @@ struct fw_cfg_sysfs_entry { > > =09struct list_head list; > > }; > > =20 > > +#ifdef CONFIG_CRASH_CORE > > +static ssize_t write_vmcoreinfo(const struct fw_cfg_file *f) > > +{ > > +=09struct vmci { > > +=09=09__le16 host_format; > > +=09=09__le16 guest_format; > > +=09=09__le32 size; > > +=09=09__le64 paddr; > > +=09} __packed; > > +=09struct vmci *data; > > +=09ssize_t ret; > > + > > +=09data =3D kmalloc(sizeof(struct vmci), GFP_KERNEL | GFP_DMA); > > +=09if (!data) > > +=09=09return -ENOMEM; >=20 > It's a small bit of data - you can just keep it in a global variable, > this way failures won't be an issue. It would still need to be allocated with GFP_DMA. Since it's a one time thi= ng, this is just moving the problem isn't it? >=20 > > + > > +=09/* spare ourself reading host format support for now since we > > +=09 * don't know what else to format - host may ignore ours > > +=09 */ > > +=09*data =3D (struct vmci) { > > +=09=09.guest_format =3D cpu_to_le16(VMCOREINFO_FORMAT_ELF), > > +=09=09.size =3D cpu_to_le32(VMCOREINFO_NOTE_SIZE), > > +=09=09.paddr =3D cpu_to_le64(paddr_vmcoreinfo_note()) > > +=09}; > > +=09ret =3D fw_cfg_write_blob(f->select, data, 0, sizeof(struct vmci)); > > + > > +=09kfree(data); > > +=09return ret; > > +} > > +#endif /* CONFIG_CRASH_CORE */ > > + > > /* get fw_cfg_sysfs_entry from kobject member */ > > static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj= ) > > { > > @@ -582,6 +660,13 @@ static int fw_cfg_register_file(const struct > > fw_cfg_file *f) > > =09int err; > > =09struct fw_cfg_sysfs_entry *entry; > > =20 > > +#ifdef CONFIG_CRASH_CORE > > +=09if (strcmp(f->name, "etc/vmcoreinfo") =3D=3D 0 && !is_kdump_kernel(= )) { > > +=09=09if (write_vmcoreinfo(f) < 0) > > +=09=09=09pr_warn("fw_cfg: failed to write vmcoreinfo"); > > +=09} > > +#endif > > + > > =09/* allocate new entry */ > > =09entry =3D kzalloc(sizeof(*entry), GFP_KERNEL); > > =09if (!entry) > > -- > > 2.15.0.125.g8f49766d64 >=20