From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49521) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aK4MO-0004DA-3D for qemu-devel@nongnu.org; Fri, 15 Jan 2016 08:24:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aK4ML-0001nK-4a for qemu-devel@nongnu.org; Fri, 15 Jan 2016 08:24:12 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:42966) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aK4MK-0001n5-Tb for qemu-devel@nongnu.org; Fri, 15 Jan 2016 08:24:09 -0500 From: Ian Campbell Date: Fri, 15 Jan 2016 13:23:40 +0000 Message-ID: <1452864224-2554-5-git-send-email-ian.campbell@citrix.com> In-Reply-To: <1452864224-2554-1-git-send-email-ian.campbell@citrix.com> References: <1452864168.32341.97.camel@citrix.com> <1452864224-2554-1-git-send-email-ian.campbell@citrix.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH QEMU-XEN v8 4/8] xen: Switch uses of xc_map_foreign_range into xc_map_foreign_pages List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: ian.jackson@eu.citrix.com, wei.liu2@citrix.com, xen-devel@lists.xen.org Cc: Ian Campbell , qemu-devel@nongnu.org, stefano.stabellini@eu.citrix.com In Xen 4.7 we are refactoring parts libxenctrl into a number of separate libraries which will provide backward and forward API and ABI compatiblity. One such library will be libxenforeignmemory which provides access to privileged foreign mappings and which will provide an interface equivalent to xc_map_foreign_{pages,bulk}. In preparation for this switch all uses of xc_map_foreign_range to xc_map_foreign_pages. This is trivial because size was always XC_PAGE_SIZE so the necessary adjustments are trivial: * Pass &mfn (an array of length 1) instead of mfn. The function takes a pointer to const, so there is no possibily of mfn changing due to this change. * Pass nr_pages=1 instead of size=XC_PAGE_SIZE There is one wrinkle in xen_console.c:con_initialise() where con->ring_ref is an int but can in some code paths (when !xendev->dev) be treated as an mfn. I think this is an existing latent truncation hazard on platforms where xen_pfn_t is 64-bit and int is 32-bit (e.g. amd64, both arm* variants). I'm unsure under what circumstances xendev->dev can be NULL or if anything elsewhere ensures the value fits into an int. For now I just use a temporary xen_pfn_t to in effect upcast the pointer from int* to xen_pfn_t*. In xenfb.c:common_bind we now explicitly launder the mfn into a xen_pfn_t, so it has the correct type to be passed to xc_map_foreign_pages and doesn't provoke warnings on 32-bit x86. Signed-off-by: Ian Campbell Reviewed-by: Stefano Stabellini --- v7: Correct type mismatch (int64 vs xen_pfn_t) on 32 bit x86 in xenfb.c, by explicitly laundering via a xen_pfn_t variable. v6: Switch to xc_map_foreign_pages rather than _bulk. Switching to _bulk without checking the value of err[0] risked missing errors. The new xenforeignmemory_map coming later in this series will DTRT with err==NULL. Dropped Stefano's Reviewed-by due to this change. v4: Ran checkpatch, fixed all errors Mention the const-ness of the mfn array in the commit log fixup!xen: Switch uses of xc_map_foreign_range into xc_map_foreign_pages --- hw/char/xen_console.c | 8 ++++---- hw/display/xenfb.c | 15 ++++++++------- xen-hvm.c | 14 +++++++------- 3 files changed, 19 insertions(+), 18 deletions(-) diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c index ac1b324..3e8a57b 100644 --- a/hw/char/xen_console.c +++ b/hw/char/xen_console.c @@ -228,10 +228,10 @@ static int con_initialise(struct XenDevice *xendev) con->buffer.max_capacity = limit; if (!xendev->dev) { - con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom, - XC_PAGE_SIZE, - PROT_READ|PROT_WRITE, - con->ring_ref); + xen_pfn_t mfn = con->ring_ref; + con->sring = xc_map_foreign_pages(xen_xc, con->xendev.dom, + PROT_READ|PROT_WRITE, + &mfn, 1); } else { con->sring = xengnttab_map_grant_ref(xendev->gnttabdev, con->xendev.dom, con->ring_ref, diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c index 4e2a27a..bb8f6b3 100644 --- a/hw/display/xenfb.c +++ b/hw/display/xenfb.c @@ -95,23 +95,24 @@ struct XenFB { static int common_bind(struct common *c) { - uint64_t mfn; + uint64_t val; + xen_pfn_t mfn; - if (xenstore_read_fe_uint64(&c->xendev, "page-ref", &mfn) == -1) + if (xenstore_read_fe_uint64(&c->xendev, "page-ref", &val) == -1) return -1; - assert(mfn == (xen_pfn_t)mfn); + mfn = (xen_pfn_t)val; + assert(val == mfn); if (xenstore_read_fe_int(&c->xendev, "event-channel", &c->xendev.remote_port) == -1) return -1; - c->page = xc_map_foreign_range(xen_xc, c->xendev.dom, - XC_PAGE_SIZE, - PROT_READ | PROT_WRITE, mfn); + c->page = xc_map_foreign_pages(xen_xc, c->xendev.dom, + PROT_READ | PROT_WRITE, &mfn, 1); if (c->page == NULL) return -1; xen_be_bind_evtchn(&c->xendev); - xen_be_printf(&c->xendev, 1, "ring mfn %"PRIx64", remote-port %d, local-port %d\n", + xen_be_printf(&c->xendev, 1, "ring mfn %"PRI_xen_pfn", remote-port %d, local-port %d\n", mfn, c->xendev.remote_port, c->xendev.local_port); return 0; diff --git a/xen-hvm.c b/xen-hvm.c index 6227e17..1f729f6 100644 --- a/xen-hvm.c +++ b/xen-hvm.c @@ -1247,8 +1247,9 @@ int xen_hvm_init(PCMachineState *pcms, DPRINTF("buffered io page at pfn %lx\n", bufioreq_pfn); DPRINTF("buffered io evtchn is %x\n", bufioreq_evtchn); - state->shared_page = xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE, - PROT_READ|PROT_WRITE, ioreq_pfn); + state->shared_page = xc_map_foreign_pages(xen_xc, xen_domid, + PROT_READ|PROT_WRITE, + &ioreq_pfn, 1); if (state->shared_page == NULL) { hw_error("map shared IO page returned error %d handle=" XC_INTERFACE_FMT, errno, xen_xc); @@ -1258,8 +1259,8 @@ int xen_hvm_init(PCMachineState *pcms, if (!rc) { DPRINTF("shared vmport page at pfn %lx\n", ioreq_pfn); state->shared_vmport_page = - xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE, - PROT_READ|PROT_WRITE, ioreq_pfn); + xc_map_foreign_pages(xen_xc, xen_domid, PROT_READ|PROT_WRITE, + &ioreq_pfn, 1); if (state->shared_vmport_page == NULL) { hw_error("map shared vmport IO page returned error %d handle=" XC_INTERFACE_FMT, errno, xen_xc); @@ -1268,10 +1269,9 @@ int xen_hvm_init(PCMachineState *pcms, hw_error("get vmport regs pfn returned error %d, rc=%d", errno, rc); } - state->buffered_io_page = xc_map_foreign_range(xen_xc, xen_domid, - XC_PAGE_SIZE, + state->buffered_io_page = xc_map_foreign_pages(xen_xc, xen_domid, PROT_READ|PROT_WRITE, - bufioreq_pfn); + &bufioreq_pfn, 1); if (state->buffered_io_page == NULL) { hw_error("map buffered IO page returned error %d", errno); } -- 2.1.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: [PATCH QEMU-XEN v8 4/8] xen: Switch uses of xc_map_foreign_range into xc_map_foreign_pages Date: Fri, 15 Jan 2016 13:23:40 +0000 Message-ID: <1452864224-2554-5-git-send-email-ian.campbell@citrix.com> References: <1452864168.32341.97.camel@citrix.com> <1452864224-2554-1-git-send-email-ian.campbell@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1452864224-2554-1-git-send-email-ian.campbell@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: ian.jackson@eu.citrix.com, wei.liu2@citrix.com, xen-devel@lists.xen.org Cc: Ian Campbell , qemu-devel@nongnu.org, stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org In Xen 4.7 we are refactoring parts libxenctrl into a number of separate libraries which will provide backward and forward API and ABI compatiblity. One such library will be libxenforeignmemory which provides access to privileged foreign mappings and which will provide an interface equivalent to xc_map_foreign_{pages,bulk}. In preparation for this switch all uses of xc_map_foreign_range to xc_map_foreign_pages. This is trivial because size was always XC_PAGE_SIZE so the necessary adjustments are trivial: * Pass &mfn (an array of length 1) instead of mfn. The function takes a pointer to const, so there is no possibily of mfn changing due to this change. * Pass nr_pages=1 instead of size=XC_PAGE_SIZE There is one wrinkle in xen_console.c:con_initialise() where con->ring_ref is an int but can in some code paths (when !xendev->dev) be treated as an mfn. I think this is an existing latent truncation hazard on platforms where xen_pfn_t is 64-bit and int is 32-bit (e.g. amd64, both arm* variants). I'm unsure under what circumstances xendev->dev can be NULL or if anything elsewhere ensures the value fits into an int. For now I just use a temporary xen_pfn_t to in effect upcast the pointer from int* to xen_pfn_t*. In xenfb.c:common_bind we now explicitly launder the mfn into a xen_pfn_t, so it has the correct type to be passed to xc_map_foreign_pages and doesn't provoke warnings on 32-bit x86. Signed-off-by: Ian Campbell Reviewed-by: Stefano Stabellini --- v7: Correct type mismatch (int64 vs xen_pfn_t) on 32 bit x86 in xenfb.c, by explicitly laundering via a xen_pfn_t variable. v6: Switch to xc_map_foreign_pages rather than _bulk. Switching to _bulk without checking the value of err[0] risked missing errors. The new xenforeignmemory_map coming later in this series will DTRT with err==NULL. Dropped Stefano's Reviewed-by due to this change. v4: Ran checkpatch, fixed all errors Mention the const-ness of the mfn array in the commit log fixup!xen: Switch uses of xc_map_foreign_range into xc_map_foreign_pages --- hw/char/xen_console.c | 8 ++++---- hw/display/xenfb.c | 15 ++++++++------- xen-hvm.c | 14 +++++++------- 3 files changed, 19 insertions(+), 18 deletions(-) diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c index ac1b324..3e8a57b 100644 --- a/hw/char/xen_console.c +++ b/hw/char/xen_console.c @@ -228,10 +228,10 @@ static int con_initialise(struct XenDevice *xendev) con->buffer.max_capacity = limit; if (!xendev->dev) { - con->sring = xc_map_foreign_range(xen_xc, con->xendev.dom, - XC_PAGE_SIZE, - PROT_READ|PROT_WRITE, - con->ring_ref); + xen_pfn_t mfn = con->ring_ref; + con->sring = xc_map_foreign_pages(xen_xc, con->xendev.dom, + PROT_READ|PROT_WRITE, + &mfn, 1); } else { con->sring = xengnttab_map_grant_ref(xendev->gnttabdev, con->xendev.dom, con->ring_ref, diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c index 4e2a27a..bb8f6b3 100644 --- a/hw/display/xenfb.c +++ b/hw/display/xenfb.c @@ -95,23 +95,24 @@ struct XenFB { static int common_bind(struct common *c) { - uint64_t mfn; + uint64_t val; + xen_pfn_t mfn; - if (xenstore_read_fe_uint64(&c->xendev, "page-ref", &mfn) == -1) + if (xenstore_read_fe_uint64(&c->xendev, "page-ref", &val) == -1) return -1; - assert(mfn == (xen_pfn_t)mfn); + mfn = (xen_pfn_t)val; + assert(val == mfn); if (xenstore_read_fe_int(&c->xendev, "event-channel", &c->xendev.remote_port) == -1) return -1; - c->page = xc_map_foreign_range(xen_xc, c->xendev.dom, - XC_PAGE_SIZE, - PROT_READ | PROT_WRITE, mfn); + c->page = xc_map_foreign_pages(xen_xc, c->xendev.dom, + PROT_READ | PROT_WRITE, &mfn, 1); if (c->page == NULL) return -1; xen_be_bind_evtchn(&c->xendev); - xen_be_printf(&c->xendev, 1, "ring mfn %"PRIx64", remote-port %d, local-port %d\n", + xen_be_printf(&c->xendev, 1, "ring mfn %"PRI_xen_pfn", remote-port %d, local-port %d\n", mfn, c->xendev.remote_port, c->xendev.local_port); return 0; diff --git a/xen-hvm.c b/xen-hvm.c index 6227e17..1f729f6 100644 --- a/xen-hvm.c +++ b/xen-hvm.c @@ -1247,8 +1247,9 @@ int xen_hvm_init(PCMachineState *pcms, DPRINTF("buffered io page at pfn %lx\n", bufioreq_pfn); DPRINTF("buffered io evtchn is %x\n", bufioreq_evtchn); - state->shared_page = xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE, - PROT_READ|PROT_WRITE, ioreq_pfn); + state->shared_page = xc_map_foreign_pages(xen_xc, xen_domid, + PROT_READ|PROT_WRITE, + &ioreq_pfn, 1); if (state->shared_page == NULL) { hw_error("map shared IO page returned error %d handle=" XC_INTERFACE_FMT, errno, xen_xc); @@ -1258,8 +1259,8 @@ int xen_hvm_init(PCMachineState *pcms, if (!rc) { DPRINTF("shared vmport page at pfn %lx\n", ioreq_pfn); state->shared_vmport_page = - xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE, - PROT_READ|PROT_WRITE, ioreq_pfn); + xc_map_foreign_pages(xen_xc, xen_domid, PROT_READ|PROT_WRITE, + &ioreq_pfn, 1); if (state->shared_vmport_page == NULL) { hw_error("map shared vmport IO page returned error %d handle=" XC_INTERFACE_FMT, errno, xen_xc); @@ -1268,10 +1269,9 @@ int xen_hvm_init(PCMachineState *pcms, hw_error("get vmport regs pfn returned error %d, rc=%d", errno, rc); } - state->buffered_io_page = xc_map_foreign_range(xen_xc, xen_domid, - XC_PAGE_SIZE, + state->buffered_io_page = xc_map_foreign_pages(xen_xc, xen_domid, PROT_READ|PROT_WRITE, - bufioreq_pfn); + &bufioreq_pfn, 1); if (state->buffered_io_page == NULL) { hw_error("map buffered IO page returned error %d", errno); } -- 2.1.4