QEMU patches for 2018-08-20

[Qemu-devel] [PULL 05/36] hw/i386/pc: Map into memory the initrd

Paolo Bonzini posted 36 patches 6 years, 5 months ago

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Maintainers: Alistair Francis <Alistair.Francis@wdc.com>, Markus Armbruster <armbru@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Artyom Tarasenko <atar4qemu@gmail.com>, Marcelo Tosatti <mtosatti@redhat.com>, Max Filippov <jcmvbkbc@gmail.com>, Michael Roth <mdroth@linux.vnet.ibm.com>, Greg Kurz <groug@kaod.org>, Laurent Vivier <lvivier@redhat.com>, Guan Xuetao <gxt@mprc.pku.edu.cn>, Peter Maydell <peter.maydell@linaro.org>, David Gibson <david@gibson.dropbear.id.au>, Thomas Huth <thuth@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>, Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>, Kevin Wolf <kwolf@redhat.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Aleksandar Markovic <amarkovic@wavecomp.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Juan Quintela <quintela@redhat.com>, Fam Zheng <fam@euphon.net>, Michael Walle <michael@walle.cc>, Aurelien Jarno <aurelien@aurel32.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Alberto Garcia <berto@igalia.com>, Richard Henderson <rth@twiddle.net>, Marek Vasut <marex@denx.de>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Paolo Bonzini <pbonzini@redhat.com>, Max Reitz <mreitz@redhat.com>, Aleksandar Rikalo <arikalo@wavecomp.com>, Sagar Karandikar <sagark@eecs.berkeley.edu>, Palmer Dabbelt <palmer@sifive.com>, Chris Wulff <crwulff@gmail.com>, Kamil Rytarowski <kamil@netbsd.org>

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[Qemu-devel] [PULL 05/36] hw/i386/pc: Map into memory the initrd

Posted by Paolo Bonzini 6 years, 5 months ago

From: Stefano Garzarella <sgarzare@redhat.com>

In order to reduce the memory footprint we map into memory
the initrd using g_mapped_file_new() instead of reading it.
In this way we can share the initrd pages between multiple
instances of QEMU.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20190724143105.307042-4-sgarzare@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/i386/pc.c         | 17 +++++++++++++----
 include/hw/i386/pc.h |  1 +
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 549c437..96f6b89 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1241,17 +1241,21 @@ static void load_linux(PCMachineState *pcms,
 
             /* load initrd */
             if (initrd_filename) {
+                GMappedFile *mapped_file;
                 gsize initrd_size;
                 gchar *initrd_data;
                 GError *gerr = NULL;
 
-                if (!g_file_get_contents(initrd_filename, &initrd_data,
-                            &initrd_size, &gerr)) {
+                mapped_file = g_mapped_file_new(initrd_filename, false, &gerr);
+                if (!mapped_file) {
                     fprintf(stderr, "qemu: error reading initrd %s: %s\n",
                             initrd_filename, gerr->message);
                     exit(1);
                 }
+                pcms->initrd_mapped_file = mapped_file;
 
+                initrd_data = g_mapped_file_get_contents(mapped_file);
+                initrd_size = g_mapped_file_get_length(mapped_file);
                 initrd_max = pcms->below_4g_mem_size - pcmc->acpi_data_size - 1;
                 if (initrd_size >= initrd_max) {
                     fprintf(stderr, "qemu: initrd is too large, cannot support."
@@ -1378,6 +1382,7 @@ static void load_linux(PCMachineState *pcms,
 
     /* load initrd */
     if (initrd_filename) {
+        GMappedFile *mapped_file;
         gsize initrd_size;
         gchar *initrd_data;
         GError *gerr = NULL;
@@ -1387,12 +1392,16 @@ static void load_linux(PCMachineState *pcms,
             exit(1);
         }
 
-        if (!g_file_get_contents(initrd_filename, &initrd_data,
-                                 &initrd_size, &gerr)) {
+        mapped_file = g_mapped_file_new(initrd_filename, false, &gerr);
+        if (!mapped_file) {
             fprintf(stderr, "qemu: error reading initrd %s: %s\n",
                     initrd_filename, gerr->message);
             exit(1);
         }
+        pcms->initrd_mapped_file = mapped_file;
+
+        initrd_data = g_mapped_file_get_contents(mapped_file);
+        initrd_size = g_mapped_file_get_length(mapped_file);
         if (initrd_size >= initrd_max) {
             fprintf(stderr, "qemu: initrd is too large, cannot support."
                     "(max: %"PRIu32", need %"PRId64")\n",
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 859b64c..44edc69 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -42,6 +42,7 @@ struct PCMachineState {
     FWCfgState *fw_cfg;
     qemu_irq *gsi;
     PFlashCFI01 *flash[2];
+    GMappedFile *initrd_mapped_file;
 
     /* Configuration options: */
     uint64_t max_ram_below_4g;
-- 
1.8.3.1