libstore: Add apple-virt to system features when available

I'm sure that we'll adjust the implementation over time, but this
at least discerns between an apple silicon bare metal machine and
a tart VM.

(cherry picked from commit 9277eb276bf0a942e88fcf499f6a6b9c262be853)
This commit is contained in:
Robert Hensing 2023-10-19 16:59:35 +02:00
parent 184a20ec04
commit af21431140
2 changed files with 32 additions and 0 deletions

View file

@ -24,6 +24,9 @@
#include "config-impl.hh"
#ifdef __APPLE__
#include <sys/sysctl.h>
#endif
namespace nix {
@ -154,6 +157,29 @@ unsigned int Settings::getDefaultCores()
return concurrency;
}
#if __APPLE__
static bool hasVirt() {
int hasVMM;
int hvSupport;
size_t size;
size = sizeof(hasVMM);
if (sysctlbyname("kern.hv_vmm_present", &hasVMM, &size, NULL, 0) == 0) {
if (hasVMM)
return false;
}
// whether the kernel and hardware supports virt
size = sizeof(hvSupport);
if (sysctlbyname("kern.hv_support", &hvSupport, &size, NULL, 0) == 0) {
return hvSupport == 1;
} else {
return false;
}
}
#endif
StringSet Settings::getDefaultSystemFeatures()
{
/* For backwards compatibility, accept some "features" that are
@ -170,6 +196,11 @@ StringSet Settings::getDefaultSystemFeatures()
features.insert("kvm");
#endif
#if __APPLE__
if (hasVirt())
features.insert("apple-virt");
#endif
return features;
}

View file

@ -708,6 +708,7 @@ public:
`kvm` feature.
This setting by default includes `kvm` if `/dev/kvm` is accessible,
`apple-virt` if hardware virtualization is available on macOS,
and the pseudo-features `nixos-test`, `benchmark` and `big-parallel`
that are used in Nixpkgs to route builds to specific machines.
)", {}, false};