From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38970) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eDrcI-0007Bc-Vk for qemu-devel@nongnu.org; Sun, 12 Nov 2017 07:44:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eDrcF-0007qb-Td for qemu-devel@nongnu.org; Sun, 12 Nov 2017 07:44:03 -0500 Received: from smtp.andrew.cmu.edu ([128.2.105.203]:52966) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eDrcF-0007qP-NC for qemu-devel@nongnu.org; Sun, 12 Nov 2017 07:43:59 -0500 Date: Sun, 12 Nov 2017 07:43:56 -0500 From: "Gabriel L. Somlo" Message-ID: <20171112124333.GF19857@hedwig.ini.cmu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20171031151938.14982-6-marcandre.lureau@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v4 5/5] fw_cfg: write vmcoreinfo details List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Cc: linux-kernel@vger.kernel.org, somlo@cmu.edu, qemu-devel@nongnu.org, mst@redhat.com On Tue, Oct 31, 2017 at 04:19:38PM +0100, Marc-Andr=E9 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=E9 Lureau Same two questions as for 3/5 earlier :) Thanks, --G > --- > 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 8ce5e49b7c62..ebd9bb134900 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) > dma_addr_t dma; > ssize_t ret =3D length; > enum dma_data_direction dir =3D > - (control & FW_CFG_DMA_CTL_READ ? DMA_FROM_DEVICE : 0); > + (control & FW_CFG_DMA_CTL_READ ? DMA_FROM_DEVICE : 0) | > + (control & FW_CFG_DMA_CTL_WRITE ? DMA_TO_DEVICE : 0); > =20 > if (address && length) { > dma_addr =3D dma_map_single(dev, address, length, dir); > @@ -225,6 +230,48 @@ static ssize_t fw_cfg_read_blob(u16 key, > return 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, > + void *buf, loff_t pos, size_t count) > +{ > + u32 glk =3D -1U; > + acpi_status status; > + ssize_t ret =3D count; > + > + /* If we have ACPI, ensure mutual exclusion against any potential > + * device access by the firmware, e.g. via AML methods: > + */ > + status =3D acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); > + if (ACPI_FAILURE(status) && status !=3D AE_NOT_CONFIGURED) { > + /* Should never get here */ > + WARN(1, "%s: Failed to lock ACPI!\n", __func__); > + memset(buf, 0, count); > + return -EBUSY; Same question as before: why not e.g. EINVAL? > + } > + > + mutex_lock(&fw_cfg_dev_lock); > + if (pos =3D=3D 0) { > + ret =3D fw_cfg_dma_transfer(buf, count, key << 16 > + | FW_CFG_DMA_CTL_SELECT > + | FW_CFG_DMA_CTL_WRITE); > + } else { > + iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl); > + ret =3D fw_cfg_dma_transfer(0, pos, FW_CFG_DMA_CTL_SKIP); NULL? > + if (ret < 0) > + goto end; > + ret =3D fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE); > + } > + > +end: > + mutex_unlock(&fw_cfg_dev_lock); > + > + acpi_release_global_lock(glk); > + > + return 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 { > struct list_head list; > }; > =20 > +#ifdef CONFIG_CRASH_CORE > +static ssize_t write_vmcoreinfo(const struct fw_cfg_file *f) > +{ > + struct vmci { > + __le16 host_format; > + __le16 guest_format; > + __le32 size; > + __le64 paddr; > + } __packed; > + struct vmci *data; > + ssize_t ret; > + > + data =3D kmalloc(sizeof(struct vmci), GFP_KERNEL | GFP_DMA); > + if (!data) > + return -ENOMEM; > + > + /* spare ourself reading host format support for now since we > + * don't know what else to format - host may ignore ours > + */ > + *data =3D (struct vmci) { > + .guest_format =3D cpu_to_le16(VMCOREINFO_FORMAT_ELF), > + .size =3D cpu_to_le32(VMCOREINFO_NOTE_SIZE), > + .paddr =3D cpu_to_le64(paddr_vmcoreinfo_note()) > + }; > + ret =3D fw_cfg_write_blob(f->select, data, 0, sizeof(struct vmci)); > + > + kfree(data); > + return 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_cf= g_file *f) > int err; > struct fw_cfg_sysfs_entry *entry; > =20 > +#ifdef CONFIG_CRASH_CORE > + if (strcmp(f->name, "etc/vmcoreinfo") =3D=3D 0 && !is_kdump_kernel())= { > + if (write_vmcoreinfo(f) < 0) > + pr_warn("fw_cfg: failed to write vmcoreinfo"); > + } > +#endif > + > /* allocate new entry */ > entry =3D kzalloc(sizeof(*entry), GFP_KERNEL); > if (!entry) > --=20 > 2.15.0.rc0.40.gaefcc5f6f >=20