| Message ID | 20240620130254.415699-5-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | host/i386: allow configuring the x86-64 baseline | expand |
On Thu, Jun 20, 2024 at 03:02:52PM +0200, Paolo Bonzini wrote: > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > meson.build | 41 ++++++++++++++++++++++++++++------- > meson_options.txt | 3 +++ > scripts/meson-buildoptions.sh | 3 +++ > 3 files changed, 39 insertions(+), 8 deletions(-) > > diff --git a/meson.build b/meson.build > index 97e00d6f59b..6e694ecd9fe 100644 > --- a/meson.build > +++ b/meson.build > @@ -336,15 +336,40 @@ if host_arch == 'i386' and not cc.links(''' > qemu_common_flags = ['-march=i486'] + qemu_common_flags > endif > > -# Assume x86-64-v2 (minus CMPXCHG16B for 32-bit code) > -if host_arch == 'i386' > - qemu_common_flags = ['-mfpmath=sse'] + qemu_common_flags > -endif > +# Pick x86-64 baseline version > if host_arch in ['i386', 'x86_64'] > - qemu_common_flags = ['-mpopcnt', '-msse4.2'] + qemu_common_flags > -endif > -if host_arch == 'x86_64' > - qemu_common_flags = ['-mcx16'] + qemu_common_flags > + if get_option('x86_version') == '0' and host_arch == 'x86_64' > + error('x86_64-v1 required for x86-64 hosts') > + endif > + > + # add flags for individual instruction set extensions > + if get_option('x86_version') >= '1' > + if host_arch == 'i386' > + qemu_common_flags = ['-mfpmath=sse'] + qemu_common_flags > + else > + # present on basically all processors but technically not part of > + # x86-64-v1, so only include -mneeded for x86-64 version 2 and above > + qemu_common_flags = ['-mcx16'] + qemu_common_flags > + endif > + endif > + if get_option('x86_version') >= '2' > + qemu_common_flags = ['-mpopcnt'] + qemu_common_flags > + qemu_common_flags = cc.get_supported_arguments('-mneeded') + qemu_common_flags > + endif > + if get_option('x86_version') >= '3' > + qemu_common_flags = ['-mmovbe', '-mabm', '-mbmi1', '-mbmi2', '-mfma', '-mf16c'] + qemu_common_flags > + endif > + > + # add required vector instruction set (each level implies those below) > + if get_option('x86_version') == '1' > + qemu_common_flags = ['-msse2'] + qemu_common_flags > + elif get_option('x86_version') == '2' > + qemu_common_flags = ['-msse4.2'] + qemu_common_flags > + elif get_option('x86_version') == '3' > + qemu_common_flags = ['-mavx2'] + qemu_common_flags > + elif get_option('x86_version') == '4' > + qemu_common_flags = ['-mavx512f', '-mavx512bw', '-mavx512cd', '-mavx512dq', '-mavx512vl'] + qemu_common_flags > + endif > endif Any particular reason you chose to list various instructions individually rather than just ask GCC for the full ABI ? I'd think all of the above condences down to just # add flags for individual instruction set extensions if get_option('x86_version') >= '1' if host_arch == 'i386' qemu_common_flags = ['-mfpmath=sse'] + qemu_common_flags else # present on basically all processors but technically not part of # x86-64-v1, so only include -mneeded for x86-64 version 2 and above qemu_common_flags = ['-mcx16'] + qemu_common_flags endif endif if get_option('x86_version') >= '2' qemu_common_flags = ['-march=x86-64-v' + get_option('x86_version'), '-mneeded'] + qemu_common_flags endif With regards, Daniel
On Thu, Jun 20, 2024 at 4:55 PM Daniel P. Berrangé <berrange@redhat.com> wrote: > Any particular reason you chose to list various instructions individually > rather than just ask GCC for the full ABI ? I'd think all of the above > condences down to just To avoid that the default ('1') forces a lower level than the compiler default. Something like what you propose below could work by adding a 'default' value to the x86_version option, that leaves the flags entirely alone apart from -mcx16. However, doing so would prevent QEMU from changing the default to x86-64-v2 in meson_options.txt, because then even a compiler that defaults to x86-64-v3 would build a QEMU with AVX2 disabled. For AVX2 specifically this is not a huge deal because the decision to use AVX2 code is mostly done at runtime; but it would be a problem for future integer instruction set extensions---for example if the distro compiler uses APX you don't want to disable it. > # add flags for individual instruction set extensions > if get_option('x86_version') >= '1' > if host_arch == 'i386' > qemu_common_flags = ['-mfpmath=sse'] + qemu_common_flags Also -msse2 here, but yes. Paolo
On 6/20/24 06:02, Paolo Bonzini wrote: > Signed-off-by: Paolo Bonzini<pbonzini@redhat.com> > --- > meson.build | 41 ++++++++++++++++++++++++++++------- > meson_options.txt | 3 +++ > scripts/meson-buildoptions.sh | 3 +++ > 3 files changed, 39 insertions(+), 8 deletions(-) Acked-by: Richard Henderson <richard.henderson@linaro.org> For -mneeded, we need gcc 11 and for enforcing GNU_PROPERTY_X86_ISA_1_NEEDED we need glibc 2.33, so: debian 12 fedora 34 ubuntu 2204 suse leap 15.6 or tumbleweed. centos stream 9 I believe the -mneeded option will be accepted by FreeBSD's clang, but the note will not be enforced by the dynamic linker at startup. However, since this is all optional, requiring an explicit configure option, I don't think any of this versioning should stand in the way. r~
diff --git a/meson.build b/meson.build index 97e00d6f59b..6e694ecd9fe 100644 --- a/meson.build +++ b/meson.build @@ -336,15 +336,40 @@ if host_arch == 'i386' and not cc.links(''' qemu_common_flags = ['-march=i486'] + qemu_common_flags endif -# Assume x86-64-v2 (minus CMPXCHG16B for 32-bit code) -if host_arch == 'i386' - qemu_common_flags = ['-mfpmath=sse'] + qemu_common_flags -endif +# Pick x86-64 baseline version if host_arch in ['i386', 'x86_64'] - qemu_common_flags = ['-mpopcnt', '-msse4.2'] + qemu_common_flags -endif -if host_arch == 'x86_64' - qemu_common_flags = ['-mcx16'] + qemu_common_flags + if get_option('x86_version') == '0' and host_arch == 'x86_64' + error('x86_64-v1 required for x86-64 hosts') + endif + + # add flags for individual instruction set extensions + if get_option('x86_version') >= '1' + if host_arch == 'i386' + qemu_common_flags = ['-mfpmath=sse'] + qemu_common_flags + else + # present on basically all processors but technically not part of + # x86-64-v1, so only include -mneeded for x86-64 version 2 and above + qemu_common_flags = ['-mcx16'] + qemu_common_flags + endif + endif + if get_option('x86_version') >= '2' + qemu_common_flags = ['-mpopcnt'] + qemu_common_flags + qemu_common_flags = cc.get_supported_arguments('-mneeded') + qemu_common_flags + endif + if get_option('x86_version') >= '3' + qemu_common_flags = ['-mmovbe', '-mabm', '-mbmi1', '-mbmi2', '-mfma', '-mf16c'] + qemu_common_flags + endif + + # add required vector instruction set (each level implies those below) + if get_option('x86_version') == '1' + qemu_common_flags = ['-msse2'] + qemu_common_flags + elif get_option('x86_version') == '2' + qemu_common_flags = ['-msse4.2'] + qemu_common_flags + elif get_option('x86_version') == '3' + qemu_common_flags = ['-mavx2'] + qemu_common_flags + elif get_option('x86_version') == '4' + qemu_common_flags = ['-mavx512f', '-mavx512bw', '-mavx512cd', '-mavx512dq', '-mavx512vl'] + qemu_common_flags + endif endif if get_option('prefer_static') diff --git a/meson_options.txt b/meson_options.txt index 7a79dd89706..6065ed2d352 100644 --- a/meson_options.txt +++ b/meson_options.txt @@ -370,3 +370,6 @@ option('qemu_ga_version', type: 'string', value: '', option('hexagon_idef_parser', type : 'boolean', value : true, description: 'use idef-parser to automatically generate TCG code for the Hexagon frontend') + +option('x86_version', type : 'combo', choices : ['0', '1', '2', '3', '4'], value: '1', + description: 'tweak required x86_64 architecture version beyond compiler default') diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh index 58d49a447d5..62842d47e88 100644 --- a/scripts/meson-buildoptions.sh +++ b/scripts/meson-buildoptions.sh @@ -82,6 +82,8 @@ meson_options_help() { printf "%s\n" ' --with-suffix=VALUE Suffix for QEMU data/modules/config directories' printf "%s\n" ' (can be empty) [qemu]' printf "%s\n" ' --with-trace-file=VALUE Trace file prefix for simple backend [trace]' + printf "%s\n" ' --x86-version=CHOICE tweak required x86_64 architecture version beyond' + printf "%s\n" ' compiler default [1] (choices: 0/1/2/3)' printf "%s\n" '' printf "%s\n" 'Optional features, enabled with --enable-FEATURE and' printf "%s\n" 'disabled with --disable-FEATURE, default is enabled if available' @@ -552,6 +554,7 @@ _meson_option_parse() { --disable-werror) printf "%s" -Dwerror=false ;; --enable-whpx) printf "%s" -Dwhpx=enabled ;; --disable-whpx) printf "%s" -Dwhpx=disabled ;; + --x86-version=*) quote_sh "-Dx86_version=$2" ;; --enable-xen) printf "%s" -Dxen=enabled ;; --disable-xen) printf "%s" -Dxen=disabled ;; --enable-xen-pci-passthrough) printf "%s" -Dxen_pci_passthrough=enabled ;;
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- meson.build | 41 ++++++++++++++++++++++++++++------- meson_options.txt | 3 +++ scripts/meson-buildoptions.sh | 3 +++ 3 files changed, 39 insertions(+), 8 deletions(-)