[pve-devel] [PATCH v3 qemu 02/12] Write understood CPU flags into static file

[Stefan Reiter]

located at /usr/share/kvm/cpu-flags-understood-$arch

This file can be read by qemu-server's "query_understood_cpu_flags"
function, avoiding a more expensive call to QEMU.

For now, only x86_64 is implemented, since aarch64 doesn't print any flags when
called this way.

Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
---

v5: check for empty file

 debian/rules | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/debian/rules b/debian/rules
index 8f428c7..bc43ade 100755
--- a/debian/rules
+++ b/debian/rules
@@ -21,6 +21,8 @@ ARCH ?= $(shell dpkg-architecture -qDEB_HOST_GNU_CPU)
 PACKAGE=pve-qemu-kvm
 destdir := $(CURDIR)/debian/$(PACKAGE)
 
+flagfile := $(destdir)/usr/share/kvm/cpu-flags-understood-x86_64
+
 CFLAGS = -Wall
 
 ifneq (,$(findstring noopt,$(DEB_BUILD_OPTIONS)))
@@ -128,6 +130,18 @@ install: build
 	rm -Rf $(destdir)/usr/include
 	rm -Rf $(destdir)/usr/lib*
 
+	# write files for understood CPU flags, since these are static for every
+	# version (saves a QEMU call in qemu-server at runtime)
+	$(destdir)/usr/bin/qemu-system-x86_64 -cpu help \
+		| perl -0777 -pe ' \
+			s/^.*Recognized CPUID flags://s; # remove up to flags \
+			s/\n{2,}.*$$//s; # remove any trailing text \
+			s/\s{2,}|\n/\s/g; # remove unnecessary whitespace \
+		' > $(flagfile)
+
+	# check that file is not empty
+	[ -s $(flagfile) ]
+
 # Build architecture-independent files here.
 binary-indep: build install
 # We have nothing to do by default.
-- 
2.20.1