| Message ID | 1470758127-17769-2-git-send-email-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 9 August 2016 at 16:55, Alex Bennée <alex.bennee@linaro.org> wrote: > Emulating 64 bit guests on a 32 bit host is either impossible with KVM > or needs a lot of special casing for TCG targets. As 64 bit hosts are > fairly normal nowadays and there can't be many people trying this > combination lets disable it completely. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > --- > configure | 34 +++++++++++++++++++++++++++++++++- > 1 file changed, 33 insertions(+), 1 deletion(-) > > diff --git a/configure b/configure > index f57fcc6..7b779c1 100755 > --- a/configure > +++ b/configure > @@ -478,6 +478,7 @@ elif check_define __x86_64__ ; then > cpu="x32" > else > cpu="x86_64" > + cpu_width=64 > fi > elif check_define __sparc__ ; then > if check_define __arch64__ ; then > @@ -515,26 +516,36 @@ ARCH= > # Normalise host CPU name and set ARCH. > # Note that this case should only have supported host CPUs, not guests. > case "$cpu" in > - ia64|ppc|ppc64|s390|s390x|sparc64|x32) > + ppc|s390|x32) > cpu="$cpu" > + cpu_width=32 > + ;; > + ia64|ppc64|s390x|sparc64) > + cpu="$cpu" > + cpu_width=64 We can detect the host pointer width generically at configure time, in a similar way to how we detect its endianness: cat > $TMPC << EOF #include <inttypes.h> uintptr_t be[] = { (uintptr_t)0x4c6f4e674c6f4e67ULL }; uintptr_t le[] = { (uintptr_t)0x674e6f4c674e6f4cULL }; extern int foo(uintptr_t *a, uintptr_t *b); int main(void) { return foo(le, be); } EOF if compile_object; then if grep -q LoNgLoNg $TMPO; then hostwidth=64 elif grep -q LoNg $TMPO; then hostwidth=32 else error_exit "Host pointer width detection failed" fi else error_exit "Host pointer width detection failed" fi (I've tested the C code here but not the shell-scriptery.) > ########################################## > +# host address width checks > +too_wide_targets="" > + > +if test "$cpu_width" = "32"; then > + for target in $target_list; do > + target_name=$(echo $target | cut -d '-' -f 1) > + case "$target_name" in > + aarch64|mips64|ppc64|s390x|sparc64) We should find a way to avoid having to specify the guest CPU's pointer width twice (once here and once by setting TARGET_LONG_BITS in its cpu.h). Otherwise people are going to forget to update this list for new CPUs. > + too_wide_targets="$too_wide_targets $target" > + ;; > + esac > + done > +fi > + > +if test ! -z "$too_wide_targets" ; then > + error_exit "Support for the following targets can't be built on 32 bit systems:\n\t$too_wide_targets" > +fi Won't this break running configure on a 32-bit host with no target-list specified at all? thanks -- PMM
On 08/09/2016 09:25 PM, Alex Bennée wrote: > - ia64|ppc|ppc64|s390|s390x|sparc64|x32) > + ppc|s390|x32) > cpu="$cpu" > + cpu_width=32 > + ;; > + ia64|ppc64|s390x|sparc64) > + cpu="$cpu" > + cpu_width=64 > ;; > i386|i486|i586|i686|i86pc|BePC) > cpu="i386" > + cpu_width=32 > ;; > x86_64|amd64) > cpu="x86_64" > + cpu_width=64 > ;; > armv*b|armv*l|arm) > cpu="arm" > + cpu_width=32 > ;; > aarch64) > cpu="aarch64" > + cpu_width=32 > ;; > mips*) > cpu="mips" > ;; > sparc|sun4[cdmuv]) > cpu="sparc" > + cpu_width=32 Note that x32 and sparc are both 64-bit hosts with 32-bit pointers (we don't support sparcv8 as a host anymore, just sparcv8+, aka sparcv9 in a 32-bit context). Not that I believe these to be interesting hosts, since VMA space is half the battle when it comes to emulation. r~
diff --git a/configure b/configure index f57fcc6..7b779c1 100755 --- a/configure +++ b/configure @@ -478,6 +478,7 @@ elif check_define __x86_64__ ; then cpu="x32" else cpu="x86_64" + cpu_width=64 fi elif check_define __sparc__ ; then if check_define __arch64__ ; then @@ -515,26 +516,36 @@ ARCH= # Normalise host CPU name and set ARCH. # Note that this case should only have supported host CPUs, not guests. case "$cpu" in - ia64|ppc|ppc64|s390|s390x|sparc64|x32) + ppc|s390|x32) cpu="$cpu" + cpu_width=32 + ;; + ia64|ppc64|s390x|sparc64) + cpu="$cpu" + cpu_width=64 ;; i386|i486|i586|i686|i86pc|BePC) cpu="i386" + cpu_width=32 ;; x86_64|amd64) cpu="x86_64" + cpu_width=64 ;; armv*b|armv*l|arm) cpu="arm" + cpu_width=32 ;; aarch64) cpu="aarch64" + cpu_width=32 ;; mips*) cpu="mips" ;; sparc|sun4[cdmuv]) cpu="sparc" + cpu_width=32 ;; *) # This will result in either an error or falling back to TCI later @@ -1700,6 +1711,26 @@ else fi ########################################## +# host address width checks +too_wide_targets="" + +if test "$cpu_width" = "32"; then + for target in $target_list; do + target_name=$(echo $target | cut -d '-' -f 1) + case "$target_name" in + aarch64|mips64|ppc64|s390x|sparc64) + too_wide_targets="$too_wide_targets $target" + ;; + esac + done +fi + +if test ! -z "$too_wide_targets" ; then + error_exit "Support for the following targets can't be built on 32 bit systems:\n\t$too_wide_targets" +fi + + +########################################## # cocoa implies not SDL or GTK # (the cocoa UI code currently assumes it is always the active UI # and doesn't interact well with other UI frontend code) @@ -4795,6 +4826,7 @@ if test "$slirp" = "yes" ; then fi echo "module support $modules" echo "host CPU $cpu" +echo "host CPU width $cpu_width" echo "host big endian $bigendian" echo "target list $target_list" echo "tcg debug enabled $debug_tcg"
Emulating 64 bit guests on a 32 bit host is either impossible with KVM or needs a lot of special casing for TCG targets. As 64 bit hosts are fairly normal nowadays and there can't be many people trying this combination lets disable it completely. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- configure | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-)