[gentoo-commits] repo/gentoo:master commit in: app-emulation/qemu/files/, app-emulation/qemu/

[John Helmert III]

commit:     4da484b352e21676d7e0b13c5aa54db2a69c8271
Author:     John Helmert III <ajak <AT> gentoo <DOT> org>
AuthorDate: Sat Jan  1 01:10:55 2022 +0000
Commit:     John Helmert III <ajak <AT> gentoo <DOT> org>
CommitDate: Sat Jan  1 01:22:09 2022 +0000
URL:        https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=4da484b3

app-emulation/qemu: fix some automagic and patch runtime crash

Fix automagic audio backend use/linking (alsa, jack, oss, pulseaudio)
and pam, add upstream patches to fix crash when with user-provided
SLIC table, and fix calculating the --audio-drv-list argument.

Bug: https://bugs.gentoo.org/830170
Thanks-To: Ionen Wolkens <ionen <AT> gentoo.org>
Signed-off-by: John Helmert III <ajak <AT> gentoo.org>

 .../qemu/files/qemu-6.2.0-user-SLIC-crash.patch    | 168 ++++
 app-emulation/qemu/qemu-6.2.0-r1.ebuild            | 922 +++++++++++++++++++++
 2 files changed, 1090 insertions(+)

diff --git a/app-emulation/qemu/files/qemu-6.2.0-user-SLIC-crash.patch b/app-emulation/qemu/files/qemu-6.2.0-user-SLIC-crash.patch
new file mode 100644
index 000000000000..7d22feeade2a
--- /dev/null
+++ b/app-emulation/qemu/files/qemu-6.2.0-user-SLIC-crash.patch
@@ -0,0 +1,168 @@
+commit dce6c86f54eab61028e110497c222e73381379df
+Author: Igor Mammedov <imammedo@××××××.com>
+Date:   Mon Dec 27 14:31:17 2021 -0500
+
+    acpi: fix QEMU crash when started with SLIC table
+    
+    if QEMU is started with used provided SLIC table blob,
+    
+      -acpitable sig=SLIC,oem_id='CRASH ',oem_table_id="ME",oem_rev=00002210,asl_compiler_id="",asl_compiler_rev=00000000,data=/dev/null
+    it will assert with:
+    
+      hw/acpi/aml-build.c:61:build_append_padded_str: assertion failed: (len <= maxlen)
+    
+    and following backtrace:
+    
+      ...
+      build_append_padded_str (array=0x555556afe320, str=0x555556afdb2e "CRASH ME", maxlen=0x6, pad=0x20) at hw/acpi/aml-build.c:61
+      acpi_table_begin (desc=0x7fffffffd1b0, array=0x555556afe320) at hw/acpi/aml-build.c:1727
+      build_fadt (tbl=0x555556afe320, linker=0x555557ca3830, f=0x7fffffffd318, oem_id=0x555556afdb2e "CRASH ME", oem_table_id=0x555556afdb34 "ME") at hw/acpi/aml-build.c:2064
+      ...
+    
+    which happens due to acpi_table_begin() expecting NULL terminated
+    oem_id and oem_table_id strings, which is normally the case, but
+    in case of user provided SLIC table, oem_id points to table's blob
+    directly and as result oem_id became longer than expected.
+    
+    Fix issue by handling oem_id consistently and make acpi_get_slic_oem()
+    return NULL terminated strings.
+    
+    PS:
+    After [1] refactoring, oem_id semantics became inconsistent, where
+    NULL terminated string was coming from machine and old way pointer
+    into byte array coming from -acpitable option. That used to work
+    since build_header() wasn't expecting NULL terminated string and
+    blindly copied the 1st 6 bytes only.
+    
+    However commit [2] broke that by replacing build_header() with
+    acpi_table_begin(), which was expecting NULL terminated string
+    and was checking oem_id size.
+    
+    1) 602b45820 ("acpi: Permit OEM ID and OEM table ID fields to be changed")
+    2)
+    Fixes: 4b56e1e4eb08 ("acpi: build_fadt: use acpi_table_begin()/acpi_table_end() instead of build_header()")
+    Resolves: https://gitlab.com/qemu-project/qemu/-/issues/786
+    Signed-off-by: Igor Mammedov <imammedo@××××××.com>
+
+diff --git a/hw/acpi/core.c b/hw/acpi/core.c
+index 1e004d0078..3e811bf03c 100644
+--- a/hw/acpi/core.c
++++ b/hw/acpi/core.c
+@@ -345,8 +345,8 @@ int acpi_get_slic_oem(AcpiSlicOem *oem)
+         struct acpi_table_header *hdr = (void *)(u - sizeof(hdr->_length));
+ 
+         if (memcmp(hdr->sig, "SLIC", 4) == 0) {
+-            oem->id = hdr->oem_id;
+-            oem->table_id = hdr->oem_table_id;
++            oem->id = g_strndup(hdr->oem_id, 6);
++            oem->table_id = g_strndup(hdr->oem_table_id, 8);
+             return 0;
+         }
+     }
+diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
+index a99c6e4fe3..570f82997b 100644
+--- a/hw/i386/acpi-build.c
++++ b/hw/i386/acpi-build.c
+@@ -2721,6 +2721,8 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
+ 
+     /* Cleanup memory that's no longer used. */
+     g_array_free(table_offsets, true);
++    g_free(slic_oem.id);
++    g_free(slic_oem.table_id);
+ }
+ 
+ static void acpi_ram_update(MemoryRegion *mr, GArray *data)
+
+commit a22de122ad03ea40953ad0328b2c3e31002d8052
+Author: Igor Mammedov <imammedo@××××××.com>
+Date:   Mon Dec 27 14:31:18 2021 -0500
+
+    tests: acpi: whitelist expected blobs before changing them
+    
+    Signed-off-by: Igor Mammedov <imammedo@××××××.com>
+
+diff --git a/tests/data/acpi/q35/FACP.slic b/tests/data/acpi/q35/FACP.slic
+new file mode 100644
+index 0000000000..f6a864cc86
+Binary files /dev/null and b/tests/data/acpi/q35/FACP.slic differ
+diff --git a/tests/data/acpi/q35/SLIC.slic b/tests/data/acpi/q35/SLIC.slic
+new file mode 100644
+index 0000000000..e69de29bb2
+diff --git a/tests/qtest/bios-tables-test-allowed-diff.h b/tests/qtest/bios-tables-test-allowed-diff.h
+index dfb8523c8b..49dbf8fa3e 100644
+--- a/tests/qtest/bios-tables-test-allowed-diff.h
++++ b/tests/qtest/bios-tables-test-allowed-diff.h
+@@ -1 +1,3 @@
+ /* List of comma-separated changed AML files to ignore */
++"tests/data/acpi/q35/FACP.slic",
++"tests/data/acpi/q35/SLIC.slic",
+
+commit cb913395d76f8fdfd7f1d0c8ea77d4710821bbd3
+Author: Igor Mammedov <imammedo@××××××.com>
+Date:   Mon Dec 27 14:31:19 2021 -0500
+
+    tests: acpi: add SLIC table test
+    
+    When user uses '-acpitable' to add SLIC table, some ACPI
+    tables (FADT) will change its 'Oem ID'/'Oem Table ID' fields to
+    match that of SLIC. Test makes sure thati QEMU handles
+    those fields correctly when SLIC table is added with
+    '-acpitable' option.
+    
+    Signed-off-by: Igor Mammedov <imammedo@××××××.com>
+
+diff --git a/tests/qtest/bios-tables-test.c b/tests/qtest/bios-tables-test.c
+index 258874167e..ae7ef13ec7 100644
+--- a/tests/qtest/bios-tables-test.c
++++ b/tests/qtest/bios-tables-test.c
+@@ -1567,6 +1567,19 @@ static void test_acpi_oem_fields_virt(void)
+     g_free(args);
+ }
+
++static void test_acpi_q35_slic(void)
++{
++    test_data data = {
++        .machine = MACHINE_Q35,
++        .variant = ".slic",
++    };
++
++    test_acpi_one("-acpitable sig=SLIC,oem_id='CRASH ',oem_table_id='ME',"
++                  "oem_rev=00002210,asl_compiler_id='qemu',"
++                  "asl_compiler_rev=00000000,data=/dev/null",
++                  &data);
++    free_test_data(&data);
++}
+
+ int main(int argc, char *argv[])
+ {
+@@ -1639,6 +1652,7 @@ int main(int argc, char *argv[])
+             qtest_add_func("acpi/q35/kvm/xapic", test_acpi_q35_kvm_xapic);
+             qtest_add_func("acpi/q35/kvm/dmar", test_acpi_q35_kvm_dmar);
+         }
++        qtest_add_func("acpi/q35/slic", test_acpi_q35_slic);
+     } else if (strcmp(arch, "aarch64") == 0) {
+         if (has_tcg) {
+             qtest_add_func("acpi/virt", test_acpi_virt_tcg);
+
+commit ffba261306370e0ad8506401b104be5fa4749ade
+Author: Igor Mammedov <imammedo@××××××.com>
+Date:   Mon Dec 27 14:31:20 2021 -0500
+
+    tests: acpi: SLIC: update expected blobs
+    
+    Signed-off-by: Igor Mammedov <imammedo@××××××.com>
+
+diff --git a/tests/data/acpi/q35/FACP.slic b/tests/data/acpi/q35/FACP.slic
+index f6a864cc86..891fd4b784 100644
+Binary files a/tests/data/acpi/q35/FACP.slic and b/tests/data/acpi/q35/FACP.slic differ
+diff --git a/tests/data/acpi/q35/SLIC.slic b/tests/data/acpi/q35/SLIC.slic
+index e69de29bb2..fd26592e24 100644
+Binary files a/tests/data/acpi/q35/SLIC.slic and b/tests/data/acpi/q35/SLIC.slic differ
+diff --git a/tests/qtest/bios-tables-test-allowed-diff.h b/tests/qtest/bios-tables-test-allowed-diff.h
+index 49dbf8fa3e..dfb8523c8b 100644
+--- a/tests/qtest/bios-tables-test-allowed-diff.h
++++ b/tests/qtest/bios-tables-test-allowed-diff.h
+@@ -1,3 +1 @@
+ /* List of comma-separated changed AML files to ignore */
+-"tests/data/acpi/q35/FACP.slic",
+-"tests/data/acpi/q35/SLIC.slic",

diff --git a/app-emulation/qemu/qemu-6.2.0-r1.ebuild b/app-emulation/qemu/qemu-6.2.0-r1.ebuild
new file mode 100644
index 000000000000..3f1ccc352eb5
--- /dev/null
+++ b/app-emulation/qemu/qemu-6.2.0-r1.ebuild
@@ -0,0 +1,922 @@
+# Copyright 1999-2021 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+PYTHON_COMPAT=( python3_{8,9,10} )
+PYTHON_REQ_USE="ncurses,readline"
+
+FIRMWARE_ABI_VERSION="6.2.0"
+
+inherit linux-info toolchain-funcs python-r1 udev fcaps readme.gentoo-r1 \
+		pax-utils xdg-utils
+
+if [[ ${PV} = *9999* ]]; then
+	EGIT_REPO_URI="https://git.qemu.org/git/qemu.git"
+	EGIT_SUBMODULES=(
+		meson
+		tests/fp/berkeley-softfloat-3
+		tests/fp/berkeley-testfloat-3
+		ui/keycodemapdb
+	)
+	inherit git-r3
+	SRC_URI=""
+else
+	SRC_URI="https://download.qemu.org/${P}.tar.xz"
+	KEYWORDS="~amd64 ~arm64 ~ppc ~ppc64 ~x86"
+fi
+
+DESCRIPTION="QEMU + Kernel-based Virtual Machine userland tools"
+HOMEPAGE="https://www.qemu.org https://www.linux-kvm.org"
+
+LICENSE="GPL-2 LGPL-2 BSD-2"
+SLOT="0"
+
+IUSE="accessibility +aio alsa bpf bzip2 capstone +caps +curl debug +doc
+	+fdt fuse glusterfs gnutls gtk infiniband iscsi io-uring
+	jack jemalloc +jpeg kernel_linux
+	kernel_FreeBSD lzo multipath
+	ncurses nfs nls numa opengl +oss pam +pin-upstream-blobs
+	plugins +png pulseaudio python rbd sasl +seccomp sdl sdl-image selinux
+	+slirp
+	smartcard snappy spice ssh static static-user systemtap test udev usb
+	usbredir vde +vhost-net vhost-user-fs virgl virtfs +vnc vte xattr xen
+	xfs zstd"
+
+COMMON_TARGETS="
+	aarch64
+	alpha
+	arm
+	cris
+	hppa
+	i386
+	m68k
+	microblaze
+	microblazeel
+	mips
+	mips64
+	mips64el
+	mipsel
+	nios2
+	or1k
+	ppc
+	ppc64
+	riscv32
+	riscv64
+	s390x
+	sh4
+	sh4eb
+	sparc
+	sparc64
+	x86_64
+	xtensa
+	xtensaeb
+"
+IUSE_SOFTMMU_TARGETS="
+	${COMMON_TARGETS}
+	avr
+	rx
+	tricore
+"
+IUSE_USER_TARGETS="
+	${COMMON_TARGETS}
+	aarch64_be
+	armeb
+	hexagon
+	mipsn32
+	mipsn32el
+	ppc64abi32
+	ppc64le
+	sparc32plus
+"
+
+use_softmmu_targets=$(printf ' qemu_softmmu_targets_%s' ${IUSE_SOFTMMU_TARGETS})
+use_user_targets=$(printf ' qemu_user_targets_%s' ${IUSE_USER_TARGETS})
+IUSE+=" ${use_softmmu_targets} ${use_user_targets}"
+
+RESTRICT="!test? ( test )"
+# Allow no targets to be built so that people can get a tools-only build.
+# Block USE flag configurations known to not work.
+REQUIRED_USE="${PYTHON_REQUIRED_USE}
+	qemu_softmmu_targets_arm? ( fdt )
+	qemu_softmmu_targets_microblaze? ( fdt )
+	qemu_softmmu_targets_mips64el? ( fdt )
+	qemu_softmmu_targets_ppc64? ( fdt )
+	qemu_softmmu_targets_ppc? ( fdt )
+	qemu_softmmu_targets_riscv32? ( fdt )
+	qemu_softmmu_targets_riscv64? ( fdt )
+	qemu_softmmu_targets_x86_64? ( fdt )
+	sdl-image? ( sdl )
+	static? ( static-user !alsa !gtk !jack !opengl !pulseaudio !plugins !rbd !snappy !udev )
+	static-user? ( !plugins )
+	vhost-user-fs? ( caps seccomp )
+	virgl? ( opengl )
+	virtfs? ( caps xattr )
+	vte? ( gtk )
+	multipath? ( udev )
+	plugins? ( !static !static-user )
+"
+
+# Dependencies required for qemu tools (qemu-nbd, qemu-img, qemu-io, ...)
+# and user/softmmu targets (qemu-*, qemu-system-*).
+#
+# Yep, you need both libcap and libcap-ng since virtfs only uses libcap.
+#
+# The attr lib isn't always linked in (although the USE flag is always
+# respected).  This is because qemu supports using the C library's API
+# when available rather than always using the external library.
+ALL_DEPEND="
+	>=dev-libs/glib-2.0[static-libs(+)]
+	sys-libs/zlib[static-libs(+)]
+	python? ( ${PYTHON_DEPS} )
+	systemtap? ( dev-util/systemtap )
+	xattr? ( sys-apps/attr[static-libs(+)] )"
+
+# Dependencies required for qemu tools (qemu-nbd, qemu-img, qemu-io, ...)
+# softmmu targets (qemu-system-*).
+SOFTMMU_TOOLS_DEPEND="
+	dev-libs/libxml2[static-libs(+)]
+	>=x11-libs/pixman-0.28.0[static-libs(+)]
+	accessibility? (
+		app-accessibility/brltty[api]
+		app-accessibility/brltty[static-libs(+)]
+	)
+	aio? ( dev-libs/libaio[static-libs(+)] )
+	alsa? ( >=media-libs/alsa-lib-1.0.13 )
+	bpf? ( dev-libs/libbpf:= )
+	bzip2? ( app-arch/bzip2[static-libs(+)] )
+	capstone? ( dev-libs/capstone:= )
+	caps? ( sys-libs/libcap-ng[static-libs(+)] )
+	curl? ( >=net-misc/curl-7.15.4[static-libs(+)] )
+	fdt? ( >=sys-apps/dtc-1.5.0[static-libs(+)] )
+	fuse? ( >=sys-fs/fuse-3.1:3[static-libs(+)] )
+	glusterfs? ( >=sys-cluster/glusterfs-3.4.0[static-libs(+)] )
+	gnutls? (
+		dev-libs/nettle:=[static-libs(+)]
+		>=net-libs/gnutls-3.0:=[static-libs(+)]
+	)
+	gtk? (
+		x11-libs/gtk+:3
+		vte? ( x11-libs/vte:2.91 )
+	)
+	infiniband? ( sys-cluster/rdma-core[static-libs(+)] )
+	iscsi? ( net-libs/libiscsi )
+	io-uring? ( sys-libs/liburing:=[static-libs(+)] )
+	jack? ( virtual/jack )
+	jemalloc? ( dev-libs/jemalloc )
+	jpeg? ( virtual/jpeg:0=[static-libs(+)] )
+	lzo? ( dev-libs/lzo:2[static-libs(+)] )
+	multipath? ( sys-fs/multipath-tools )
+	ncurses? (
+		sys-libs/ncurses:=[unicode(+)]
+		sys-libs/ncurses:=[static-libs(+)]
+	)
+	nfs? ( >=net-fs/libnfs-1.9.3:=[static-libs(+)] )
+	numa? ( sys-process/numactl[static-libs(+)] )
+	opengl? (
+		virtual/opengl
+		media-libs/libepoxy[static-libs(+)]
+		media-libs/mesa[static-libs(+)]
+		media-libs/mesa[egl(+),gbm(+)]
+	)
+	pam? ( sys-libs/pam )
+	png? ( media-libs/libpng:0=[static-libs(+)] )
+	pulseaudio? ( media-sound/pulseaudio )
+	rbd? ( sys-cluster/ceph )
+	sasl? ( dev-libs/cyrus-sasl[static-libs(+)] )
+	sdl? (
+		media-libs/libsdl2[video]
+		media-libs/libsdl2[static-libs(+)]
+	)
+	sdl-image? ( media-libs/sdl2-image[static-libs(+)] )
+	seccomp? ( >=sys-libs/libseccomp-2.1.0[static-libs(+)] )
+	slirp? ( net-libs/libslirp[static-libs(+)] )
+	smartcard? ( >=app-emulation/libcacard-2.5.0[static-libs(+)] )
+	snappy? ( app-arch/snappy:= )
+	spice? (
+		>=app-emulation/spice-protocol-0.12.3
+		>=app-emulation/spice-0.12.0[static-libs(+)]
+	)
+	ssh? ( >=net-libs/libssh-0.8.6[static-libs(+)] )
+	udev? ( virtual/libudev:= )
+	usb? ( >=virtual/libusb-1-r2[static-libs(+)] )
+	usbredir? ( >=sys-apps/usbredir-0.6[static-libs(+)] )
+	vde? ( net-misc/vde[static-libs(+)] )
+	virgl? ( media-libs/virglrenderer[static-libs(+)] )
+	virtfs? ( sys-libs/libcap )
+	xen? ( app-emulation/xen-tools:= )
+	xfs? ( sys-fs/xfsprogs[static-libs(+)] )
+	zstd? ( >=app-arch/zstd-1.4.0[static-libs(+)] )
+"
+
+EDK2_OVMF_VERSION="202105"
+SEABIOS_VERSION="1.14.0"
+
+X86_FIRMWARE_DEPEND="
+	pin-upstream-blobs? (
+		~sys-firmware/edk2-ovmf-${EDK2_OVMF_VERSION}[binary]
+		~sys-firmware/ipxe-1.21.1[binary,qemu]
+		~sys-firmware/seabios-${SEABIOS_VERSION}[binary,seavgabios]
+		~sys-firmware/sgabios-0.1_pre10[binary]
+	)
+	!pin-upstream-blobs? (
+		>=sys-firmware/edk2-ovmf-${EDK2_OVMF_VERSION}
+		sys-firmware/ipxe[qemu]
+		>=sys-firmware/seabios-${SEABIOS_VERSION}[seavgabios]
+		sys-firmware/sgabios
+	)"
+PPC_FIRMWARE_DEPEND="
+	pin-upstream-blobs? (
+		~sys-firmware/seabios-${SEABIOS_VERSION}[binary,seavgabios]
+	)
+	!pin-upstream-blobs? (
+		>=sys-firmware/seabios-${SEABIOS_VERSION}[seavgabios]
+	)
+"
+
+BDEPEND="
+	$(python_gen_impl_dep)
+	dev-lang/perl
+	sys-apps/texinfo
+	virtual/pkgconfig
+	doc? (
+		dev-python/sphinx[${PYTHON_USEDEP}]
+		dev-python/sphinx_rtd_theme[${PYTHON_USEDEP}]
+	)
+	gtk? ( nls? ( sys-devel/gettext ) )
+	test? (
+		dev-libs/glib[utils]
+		sys-devel/bc
+	)
+"
+CDEPEND="
+	!static? (
+		${ALL_DEPEND//\[static-libs(+)]}
+		${SOFTMMU_TOOLS_DEPEND//\[static-libs(+)]}
+	)
+	qemu_softmmu_targets_i386? ( ${X86_FIRMWARE_DEPEND} )
+	qemu_softmmu_targets_x86_64? ( ${X86_FIRMWARE_DEPEND} )
+	qemu_softmmu_targets_ppc? ( ${PPC_FIRMWARE_DEPEND} )
+	qemu_softmmu_targets_ppc64? ( ${PPC_FIRMWARE_DEPEND} )
+"
+DEPEND="${CDEPEND}
+	kernel_linux? ( >=sys-kernel/linux-headers-2.6.35 )
+	static? (
+		${ALL_DEPEND}
+		${SOFTMMU_TOOLS_DEPEND}
+	)
+	static-user? ( ${ALL_DEPEND} )"
+RDEPEND="${CDEPEND}
+	acct-group/kvm
+	selinux? ( sec-policy/selinux-qemu )"
+
+PATCHES=(
+	"${FILESDIR}"/${PN}-2.11.1-capstone_include_path.patch
+	"${FILESDIR}"/${PN}-5.2.0-disable-keymap.patch
+	"${FILESDIR}"/${PN}-6.0.0-make.patch
+	"${FILESDIR}"/${PN}-6.1.0-strings.patch
+	"${FILESDIR}"/${PN}-6.2.0-user-SLIC-crash.patch
+)
+
+QA_PREBUILT="
+	usr/share/qemu/hppa-firmware.img
+	usr/share/qemu/openbios-ppc
+	usr/share/qemu/openbios-sparc64
+	usr/share/qemu/openbios-sparc32
+	usr/share/qemu/opensbi-riscv64-generic-fw_dynamic.elf
+	usr/share/qemu/opensbi-riscv32-generic-fw_dynamic.elf
+	usr/share/qemu/palcode-clipper
+	usr/share/qemu/s390-ccw.img
+	usr/share/qemu/s390-netboot.img
+	usr/share/qemu/u-boot.e500
+"
+
+QA_WX_LOAD="usr/bin/qemu-i386
+	usr/bin/qemu-x86_64
+	usr/bin/qemu-alpha
+	usr/bin/qemu-arm
+	usr/bin/qemu-cris
+	usr/bin/qemu-m68k
+	usr/bin/qemu-microblaze
+	usr/bin/qemu-microblazeel
+	usr/bin/qemu-mips
+	usr/bin/qemu-mipsel
+	usr/bin/qemu-or1k
+	usr/bin/qemu-ppc
+	usr/bin/qemu-ppc64
+	usr/bin/qemu-ppc64abi32
+	usr/bin/qemu-sh4
+	usr/bin/qemu-sh4eb
+	usr/bin/qemu-sparc
+	usr/bin/qemu-sparc64
+	usr/bin/qemu-armeb
+	usr/bin/qemu-sparc32plus
+	usr/bin/qemu-s390x
+	usr/bin/qemu-unicore32
+"
+
+DOC_CONTENTS="If you don't have kvm compiled into the kernel, make sure you have the
+kernel module loaded before running kvm. The easiest way to ensure that the
+kernel module is loaded is to load it on boot.
+	For AMD CPUs the module is called 'kvm-amd'.
+	For Intel CPUs the module is called 'kvm-intel'.
+Please review /etc/conf.d/modules for how to load these.
+
+Make sure your user is in the 'kvm' group. Just run
+	$ gpasswd -a <USER> kvm
+then have <USER> re-login.
+
+For brand new installs, the default permissions on /dev/kvm might not let
+you access it.  You can tell udev to reset ownership/perms:
+	$ udevadm trigger -c add /dev/kvm
+
+If you want to register binfmt handlers for qemu user targets:
+For openrc:
+	# rc-update add qemu-binfmt
+For systemd:
+	# ln -s /usr/share/qemu/binfmt.d/qemu.conf /etc/binfmt.d/qemu.conf"
+
+pkg_pretend() {
+	if use kernel_linux && kernel_is lt 2 6 25; then
+		eerror "This version of KVM requires a host kernel of 2.6.25 or higher."
+	elif use kernel_linux; then
+		if ! linux_config_exists; then
+			eerror "Unable to check your kernel for KVM support"
+		else
+			CONFIG_CHECK="~KVM ~TUN ~BRIDGE"
+			ERROR_KVM="You must enable KVM in your kernel to continue"
+			ERROR_KVM_AMD="If you have an AMD CPU, you must enable KVM_AMD in"
+			ERROR_KVM_AMD+=" your kernel configuration."
+			ERROR_KVM_INTEL="If you have an Intel CPU, you must enable"
+			ERROR_KVM_INTEL+=" KVM_INTEL in your kernel configuration."
+			ERROR_TUN="You will need the Universal TUN/TAP driver compiled"
+			ERROR_TUN+=" into your kernel or loaded as a module to use the"
+			ERROR_TUN+=" virtual network device if using -net tap."
+			ERROR_BRIDGE="You will also need support for 802.1d"
+			ERROR_BRIDGE+=" Ethernet Bridging for some network configurations."
+			use vhost-net && CONFIG_CHECK+=" ~VHOST_NET"
+			ERROR_VHOST_NET="You must enable VHOST_NET to have vhost-net"
+			ERROR_VHOST_NET+=" support"
+
+			if use amd64 || use x86 || use amd64-linux || use x86-linux; then
+				if grep -q AuthenticAMD /proc/cpuinfo; then
+					CONFIG_CHECK+=" ~KVM_AMD"
+				elif grep -q GenuineIntel /proc/cpuinfo; then
+					CONFIG_CHECK+=" ~KVM_INTEL"
+				fi
+			fi
+
+			use python && CONFIG_CHECK+=" ~DEBUG_FS"
+			ERROR_DEBUG_FS="debugFS support required for kvm_stat"
+
+			# Now do the actual checks setup above
+			check_extra_config
+		fi
+	fi
+
+	if grep -qs '/usr/bin/qemu-kvm' "${EROOT}"/etc/libvirt/qemu/*.xml; then
+		eerror "The kvm/qemu-kvm wrappers no longer exist, but your libvirt"
+		eerror "instances are still pointing to it.  Please update your"
+		eerror "configs in /etc/libvirt/qemu/ to use the -enable-kvm flag"
+		eerror "and the right system binary (e.g. qemu-system-x86_64)."
+		die "update your virt configs to not use qemu-kvm"
+	fi
+}
+
+# Sanity check to make sure target lists are kept up-to-date.
+check_targets() {
+	local var=$1 mak=$2
+	local detected sorted
+
+	pushd "${S}"/configs/targets/ >/dev/null || die
+
+	# Force C locale until glibc is updated. #564936
+	detected=$(echo $(printf '%s\n' *-${mak}.mak | sed "s:-${mak}.mak::" | LC_COLLATE=C sort -u))
+	sorted=$(echo $(printf '%s\n' ${!var} | LC_COLLATE=C sort -u))
+	if [[ ${sorted} != "${detected}" ]] ; then
+		eerror "The ebuild needs to be kept in sync."
+		eerror "${var}: ${sorted}"
+		eerror "$(printf '%-*s' ${#var} configure): ${detected}"
+		die "sync ${var} to the list of targets"
+	fi
+
+	popd >/dev/null
+}
+
+src_prepare() {
+	check_targets IUSE_SOFTMMU_TARGETS softmmu
+	check_targets IUSE_USER_TARGETS linux-user
+
+	default
+
+	# Use correct toolchain to fix cross-compiling
+	tc-export AR AS LD NM OBJCOPY PKG_CONFIG RANLIB STRINGS
+	export WINDRES=${CHOST}-windres
+
+	# Verbose builds
+	MAKEOPTS+=" V=1"
+
+	# Remove bundled copy of libfdt
+	rm -r dtc || die
+}
+
+##
+# configures qemu based on the build directory and the build type
+# we are using.
+#
+qemu_src_configure() {
+	debug-print-function ${FUNCNAME} "$@"
+
+	local buildtype=$1
+	local builddir="${S}/${buildtype}-build"
+
+	mkdir "${builddir}"
+
+	local conf_opts=(
+		--prefix=/usr
+		--sysconfdir=/etc
+		--bindir=/usr/bin
+		--libdir=/usr/$(get_libdir)
+		--datadir=/usr/share
+		--docdir=/usr/share/doc/${PF}/html
+		--mandir=/usr/share/man
+		--localstatedir=/var
+		--disable-bsd-user
+		--disable-containers # bug #732972
+		--disable-guest-agent
+		--disable-strip
+
+		# bug #746752: TCG interpreter has a few limitations:
+		# - it does not support FPU
+		# - it's generally slower on non-self-modifying code
+		# It's advantage is support for host architectures
+		# where native codegeneration is not implemented.
+		# Gentoo has qemu keyworded only on targets with
+		# native code generation available. Avoid the interpreter.
+		--disable-tcg-interpreter
+
+		--disable-werror
+		# We support gnutls/nettle for crypto operations.  It is possible
+		# to use gcrypt when gnutls/nettle are disabled (but not when they
+		# are enabled), but it's not really worth the hassle.  Disable it
+		# all the time to avoid automatically detecting it. #568856
+		--disable-gcrypt
+		--python="${PYTHON}"
+		--cc="$(tc-getCC)"
+		--cxx="$(tc-getCXX)"
+		--host-cc="$(tc-getBUILD_CC)"
+		$(use_enable debug debug-info)
+		$(use_enable debug debug-tcg)
+		$(use_enable doc docs)
+		$(use_enable nls gettext)
+		$(use_enable pam auth-pam)
+		$(use_enable plugins)
+		$(use_enable xattr attr)
+		$(use_enable alsa)
+		$(use_enable jack)
+		$(use_enable oss)
+		$(use_enable pulseaudio pa)
+	)
+
+	# Disable options not used by user targets. This simplifies building
+	# static user targets (USE=static-user) considerably.
+	conf_notuser() {
+		if [[ ${buildtype} == "user" ]] ; then
+			echo "--disable-${2:-$1}"
+		else
+			use_enable "$@"
+		fi
+	}
+	# Enable option only for softmmu build, but not 'user' or 'tools'
+	conf_softmmu() {
+		if [[ ${buildtype} == "softmmu" ]] ; then
+			use_enable "$@"
+		else
+			echo "--disable-${2:-$1}"
+		fi
+	}
+	# Enable option only for tools build, but not 'user' or 'softmmu'
+	conf_tools() {
+		if [[ ${buildtype} == "tools" ]] ; then
+			use_enable "$@"
+		else
+			echo "--disable-${2:-$1}"
+		fi
+	}
+	# Special case for the malloc flag, because the --disable flag does
+	# not exist and trying like above will break configuring.
+	conf_malloc() {
+		if [[ ! ${buildtype} == "user" ]] ; then
+			usex "${1}" "--enable-malloc=${1}" ""
+		fi
+	}
+	conf_opts+=(
+		$(conf_notuser accessibility brlapi)
+		$(conf_notuser aio linux-aio)
+		$(conf_softmmu bpf)
+		$(conf_notuser bzip2)
+		$(conf_notuser capstone)
+		$(conf_notuser caps cap-ng)
+		$(conf_notuser curl)
+		$(conf_notuser fdt)
+		$(conf_notuser fuse)
+		$(conf_notuser glusterfs)
+		$(conf_notuser gnutls)
+		$(conf_notuser gnutls nettle)
+		$(conf_notuser gtk)
+		$(conf_notuser infiniband rdma)
+		$(conf_notuser iscsi libiscsi)
+		$(conf_notuser io-uring linux-io-uring)
+		$(conf_malloc jemalloc)
+		$(conf_notuser jpeg vnc-jpeg)
+		$(conf_notuser kernel_linux kvm)
+		$(conf_notuser lzo)
+		$(conf_notuser multipath mpath)
+		$(conf_notuser ncurses curses)
+		$(conf_notuser nfs libnfs)
+		$(conf_notuser numa)
+		$(conf_notuser opengl)
+		$(conf_notuser png vnc-png)
+		$(conf_notuser rbd)
+		$(conf_notuser sasl vnc-sasl)
+		$(conf_notuser sdl)
+		$(conf_softmmu sdl-image)
+		$(conf_notuser seccomp)
+		$(conf_notuser slirp slirp system)
+		$(conf_notuser smartcard)
+		$(conf_notuser snappy)
+		$(conf_notuser spice)
+		$(conf_notuser ssh libssh)
+		$(conf_notuser udev libudev)
+		$(conf_notuser usb libusb)
+		$(conf_notuser usbredir usb-redir)
+		$(conf_notuser vde)
+		$(conf_notuser vhost-net)
+		$(conf_notuser vhost-user-fs)
+		$(conf_tools vhost-user-fs virtiofsd)
+		$(conf_notuser virgl virglrenderer)
+		$(conf_softmmu virtfs)
+		$(conf_notuser vnc)
+		$(conf_notuser vte)
+		$(conf_notuser xen)
+		$(conf_notuser xen xen-pci-passthrough)
+		$(conf_notuser xfs xfsctl)
+		# use prebuilt keymaps, bug #759604
+		--disable-xkbcommon
+		$(conf_notuser zstd)
+	)
+
+	if [[ ${buildtype} == "user" ]] ; then
+		conf_opts+=( --disable-libxml2 )
+	else
+		conf_opts+=( --enable-libxml2 )
+	fi
+
+	if [[ ! ${buildtype} == "user" ]] ; then
+		# audio options
+		local audio_opts=(
+			# Note: backend order matters here: #716202
+			# We iterate from higher-level to lower level.
+			$(usex pulseaudio pa "")
+			$(usev jack)
+			$(usev sdl)
+			$(usev alsa)
+			$(usev oss)
+		)
+		conf_opts+=(
+			--audio-drv-list=$(IFS=,; echo "${audio_opts[*]}")
+		)
+	fi
+
+	case ${buildtype} in
+	user)
+		conf_opts+=(
+			--enable-linux-user
+			--disable-system
+			--disable-blobs
+			--disable-tools
+		)
+		local static_flag="static-user"
+		;;
+	softmmu)
+		conf_opts+=(
+			--disable-linux-user
+			--enable-system
+			--disable-tools
+		)
+		local static_flag="static"
+		;;
+	tools)
+		conf_opts+=(
+			--disable-linux-user
+			--disable-system
+			--disable-blobs
+			--enable-tools
+		)
+		local static_flag="static"
+		;;
+	esac
+
+	local targets="${buildtype}_targets"
+	[[ -n ${targets} ]] && conf_opts+=( --target-list="${!targets}" )
+
+	# Add support for SystemTAP
+	use systemtap && conf_opts+=( --enable-trace-backend=dtrace )
+
+	# We always want to attempt to build with PIE support as it results
+	# in a more secure binary. But it doesn't work with static or if
+	# the current GCC doesn't have PIE support.
+	if use ${static_flag}; then
+		conf_opts+=( --static --disable-pie )
+	else
+		tc-enables-pie && conf_opts+=( --enable-pie )
+	fi
+
+	# Meson will not use a cross-file unless cross_prefix is set.
+	tc-is-cross-compiler && conf_opts+=( --cross-prefix="${CHOST}-" )
+
+	# Plumb through equivalent of EXTRA_ECONF to allow experiments
+	# like bug #747928.
+	conf_opts+=( ${EXTRA_CONF_QEMU} )
+
+	echo "../configure ${conf_opts[*]}"
+	cd "${builddir}"
+	../configure "${conf_opts[@]}" || die "configure failed"
+
+	# FreeBSD's kernel does not support QEMU assigning/grabbing
+	# host USB devices yet
+	use kernel_FreeBSD && \
+		sed -i -E -e "s|^(HOST_USB=)bsd|\1stub|" "${S}"/config-host.mak
+}
+
+src_configure() {
+	local target
+
+	python_setup
+
+	softmmu_targets= softmmu_bins=()
+	user_targets= user_bins=()
+
+	for target in ${IUSE_SOFTMMU_TARGETS} ; do
+		if use "qemu_softmmu_targets_${target}"; then
+			softmmu_targets+=",${target}-softmmu"
+			softmmu_bins+=( "qemu-system-${target}" )
+		fi
+	done
+
+	for target in ${IUSE_USER_TARGETS} ; do
+		if use "qemu_user_targets_${target}"; then
+			user_targets+=",${target}-linux-user"
+			user_bins+=( "qemu-${target}" )
+		fi
+	done
+
+	softmmu_targets=${softmmu_targets#,}
+	user_targets=${user_targets#,}
+
+	[[ -n ${softmmu_targets} ]] && qemu_src_configure "softmmu"
+	[[ -n ${user_targets}    ]] && qemu_src_configure "user"
+	qemu_src_configure "tools"
+}
+
+src_compile() {
+	if [[ -n ${user_targets} ]]; then
+		cd "${S}/user-build"
+		default
+	fi
+
+	if [[ -n ${softmmu_targets} ]]; then
+		cd "${S}/softmmu-build"
+		default
+	fi
+
+	cd "${S}/tools-build"
+	default
+}
+
+src_test() {
+	if [[ -n ${softmmu_targets} ]]; then
+		cd "${S}/softmmu-build"
+		pax-mark m */qemu-system-* #515550
+		emake check
+	fi
+}
+
+qemu_python_install() {
+	python_domodule "${S}/python/qemu"
+
+	python_doscript "${S}/scripts/kvm/vmxcap"
+	python_doscript "${S}/scripts/qmp/qmp-shell"
+	python_doscript "${S}/scripts/qmp/qemu-ga-client"
+}
+
+# Generate binfmt support files.
+#   - /etc/init.d/qemu-binfmt script which registers the user handlers (openrc)
+#   - /usr/share/qemu/binfmt.d/qemu.conf (for use with systemd-binfmt)
+generate_initd() {
+	local out="${T}/qemu-binfmt"
+	local out_systemd="${T}/qemu.conf"
+	local d="${T}/binfmt.d"
+
+	einfo "Generating qemu binfmt scripts and configuration files"
+
+	# Generate the debian fragments first.
+	mkdir -p "${d}"
+	"${S}"/scripts/qemu-binfmt-conf.sh \
+		--debian \
+		--exportdir "${d}" \
+		--qemu-path "${EPREFIX}/usr/bin" \
+		|| die
+	# Then turn the fragments into a shell script we can source.
+	sed -E -i \
+		-e 's:^([^ ]+) (.*)$:\1="\2":' \
+		"${d}"/* || die
+
+	# Generate the init.d script by assembling the fragments from above.
+	local f qcpu package interpreter magic mask
+	cat "${FILESDIR}"/qemu-binfmt.initd.head >"${out}" || die
+	for f in "${d}"/qemu-* ; do
+		source "${f}"
+
+		# Normalize the cpu logic like we do in the init.d for the native cpu.
+		qcpu=${package#qemu-}
+		case ${qcpu} in
+		arm*)   qcpu="arm";;
+		mips*)  qcpu="mips";;
+		ppc*)   qcpu="ppc";;
+		s390*)  qcpu="s390";;
+		sh*)    qcpu="sh";;
+		sparc*) qcpu="sparc";;
+		esac
+
+		# we use 'printf' here to be portable across 'sh'
+		# implementations: #679168
+		cat <<EOF >>"${out}"
+	if [ "\${cpu}" != "${qcpu}" -a -x "${interpreter}" ] ; then
+		printf '%s\n' ':${package}:M::${magic}:${mask}:${interpreter}:'"\${QEMU_BINFMT_FLAGS}" >/proc/sys/fs/binfmt_misc/register
+	fi
+EOF
+
+		echo ":${package}:M::${magic}:${mask}:${interpreter}:OC" >>"${out_systemd}"
+
+	done
+	cat "${FILESDIR}"/qemu-binfmt.initd.tail >>"${out}" || die
+}
+
+src_install() {
+	if [[ -n ${user_targets} ]]; then
+		cd "${S}/user-build"
+		emake DESTDIR="${ED}" install
+
+		# Install binfmt handler init script for user targets.
+		generate_initd
+		doinitd "${T}/qemu-binfmt"
+
+		# Install binfmt/qemu.conf.
+		insinto "/usr/share/qemu/binfmt.d"
+		doins "${T}/qemu.conf"
+	fi
+
+	if [[ -n ${softmmu_targets} ]]; then
+		cd "${S}/softmmu-build"
+		emake DESTDIR="${ED}" install
+
+		# This might not exist if the test failed. #512010
+		[[ -e check-report.html ]] && dodoc check-report.html
+
+		if use kernel_linux; then
+			udev_newrules "${FILESDIR}"/65-kvm.rules-r2 65-kvm.rules
+		fi
+
+		if use python; then
+			python_foreach_impl qemu_python_install
+		fi
+	fi
+
+	cd "${S}/tools-build"
+	emake DESTDIR="${ED}" install
+
+	# Disable mprotect on the qemu binaries as they use JITs to be fast #459348
+	pushd "${ED}"/usr/bin >/dev/null
+	pax-mark mr "${softmmu_bins[@]}" "${user_bins[@]}" # bug 575594
+	popd >/dev/null
+
+	# Install config file example for qemu-bridge-helper
+	insinto "/etc/qemu"
+	doins "${FILESDIR}/bridge.conf"
+
+	cd "${S}"
+	dodoc MAINTAINERS docs/specs/pci-ids.txt
+	newdoc pc-bios/README README.pc-bios
+
+	# Disallow stripping of prebuilt firmware files.
+	dostrip -x ${QA_PREBUILT}
+
+	if [[ -n ${softmmu_targets} ]]; then
+		# Remove SeaBIOS since we're using the SeaBIOS packaged one
+		rm "${ED}/usr/share/qemu/bios.bin"
+		rm "${ED}/usr/share/qemu/bios-256k.bin"
+		if use qemu_softmmu_targets_x86_64 || use qemu_softmmu_targets_i386; then
+			dosym ../seabios/bios.bin /usr/share/qemu/bios.bin
+			dosym ../seabios/bios-256k.bin /usr/share/qemu/bios-256k.bin
+		fi
+
+		# Remove vgabios since we're using the seavgabios packaged one
+		rm "${ED}/usr/share/qemu/vgabios.bin"
+		rm "${ED}/usr/share/qemu/vgabios-cirrus.bin"
+		rm "${ED}/usr/share/qemu/vgabios-qxl.bin"
+		rm "${ED}/usr/share/qemu/vgabios-stdvga.bin"
+		rm "${ED}/usr/share/qemu/vgabios-virtio.bin"
+		rm "${ED}/usr/share/qemu/vgabios-vmware.bin"
+		# PPC/PPC64 loads vgabios-stdvga
+		if use qemu_softmmu_targets_x86_64 || use qemu_softmmu_targets_i386 || use qemu_softmmu_targets_ppc || use qemu_softmmu_targets_ppc64; then
+			dosym ../seavgabios/vgabios-isavga.bin /usr/share/qemu/vgabios.bin
+			dosym ../seavgabios/vgabios-cirrus.bin /usr/share/qemu/vgabios-cirrus.bin
+			dosym ../seavgabios/vgabios-qxl.bin /usr/share/qemu/vgabios-qxl.bin
+			dosym ../seavgabios/vgabios-stdvga.bin /usr/share/qemu/vgabios-stdvga.bin
+			dosym ../seavgabios/vgabios-virtio.bin /usr/share/qemu/vgabios-virtio.bin
+			dosym ../seavgabios/vgabios-vmware.bin /usr/share/qemu/vgabios-vmware.bin
+		fi
+
+		# Remove sgabios since we're using the sgabios packaged one
+		rm "${ED}/usr/share/qemu/sgabios.bin"
+		if use qemu_softmmu_targets_x86_64 || use qemu_softmmu_targets_i386; then
+			dosym ../sgabios/sgabios.bin /usr/share/qemu/sgabios.bin
+		fi
+
+		# Remove iPXE since we're using the iPXE packaged one
+		rm "${ED}"/usr/share/qemu/pxe-*.rom
+		if use qemu_softmmu_targets_x86_64 || use qemu_softmmu_targets_i386; then
+			dosym ../ipxe/8086100e.rom /usr/share/qemu/pxe-e1000.rom
+			dosym ../ipxe/80861209.rom /usr/share/qemu/pxe-eepro100.rom
+			dosym ../ipxe/10500940.rom /usr/share/qemu/pxe-ne2k_pci.rom
+			dosym ../ipxe/10222000.rom /usr/share/qemu/pxe-pcnet.rom
+			dosym ../ipxe/10ec8139.rom /usr/share/qemu/pxe-rtl8139.rom
+			dosym ../ipxe/1af41000.rom /usr/share/qemu/pxe-virtio.rom
+		fi
+	fi
+
+	DISABLE_AUTOFORMATTING=true
+	readme.gentoo_create_doc
+}
+
+firmware_abi_change() {
+	local pv
+	for pv in ${REPLACING_VERSIONS}; do
+		if ver_test ${pv} -lt ${FIRMWARE_ABI_VERSION}; then
+			return 0
+		fi
+	done
+	return 1
+}
+
+pkg_postinst() {
+	if [[ -n ${softmmu_targets} ]] && use kernel_linux; then
+		udev_reload
+	fi
+
+	xdg_icon_cache_update
+
+	[[ -z ${EPREFIX} ]] && [[ -f ${EROOT}/usr/libexec/qemu-bridge-helper ]] && \
+		fcaps cap_net_admin ${EROOT}/usr/libexec/qemu-bridge-helper
+
+	DISABLE_AUTOFORMATTING=true
+	readme.gentoo_print_elog
+
+	if use pin-upstream-blobs && firmware_abi_change; then
+		ewarn "This version of qemu pins new versions of firmware blobs:"
+		ewarn "	$(best_version sys-firmware/edk2-ovmf)"
+		ewarn "	$(best_version sys-firmware/ipxe)"
+		ewarn "	$(best_version sys-firmware/seabios)"
+		ewarn "	$(best_version sys-firmware/sgabios)"
+		ewarn "This might break resume of hibernated guests (started with a different"
+		ewarn "firmware version) and live migration to/from qemu versions with different"
+		ewarn "firmware. Please (cold) restart all running guests. For functional"
+		ewarn "guest migration ensure that all"
+		ewarn "hosts run at least"
+		ewarn "	app-emulation/qemu-${FIRMWARE_ABI_VERSION}."
+	fi
+}
+
+pkg_info() {
+	echo "Using:"
+	echo "  $(best_version app-emulation/spice-protocol)"
+	echo "  $(best_version sys-firmware/edk2-ovmf)"
+	if has_version 'sys-firmware/edk2-ovmf[binary]'; then
+		echo "    USE=binary"
+	else
+		echo "    USE=''"
+	fi
+	echo "  $(best_version sys-firmware/ipxe)"
+	echo "  $(best_version sys-firmware/seabios)"
+	if has_version 'sys-firmware/seabios[binary]'; then
+		echo "    USE=binary"
+	else
+		echo "    USE=''"
+	fi
+	echo "  $(best_version sys-firmware/sgabios)"
+}
+
+pkg_postrm() {
+	xdg_icon_cache_update
+}