[libvirt] [PATCH] add option to enforce minimal pagesize for hugetlbfs backed guests
Require a minimal pagesize for hugetlbfs backed guests. Fail guest initialization
if hugetlbfs mount is configured with smaller page size.
Signed-off-by: Marcelo Tosatti <mtosatti(a)redhat.com>
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index fd02864..e28d182 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -632,6 +632,10 @@
<dt><code>hugepages</code></dt>
<dd>This tells the hypervisor that the guest should have its memory
allocated using hugepages instead of the normal native page size.</dd>
+ <dt><code>pagesize</code></dt>
+ <dd>This tells the hypervisor that the guest should refuse to start
+ in case of failure to allocate guest memory with hugepages equal
+ to or larger than the specified size</dd>
<dt><code>nosharepages</code></dt>
<dd>Instructs hypervisor to disable shared pages (memory merge, KSM) for
this domain. <span class="since">Since
1.0.6</span></dd>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 28e24f9..babb745 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -11274,6 +11274,10 @@ virDomainDefParseXML(xmlDocPtr xml,
&def->mem.swap_hard_limit, false) < 0)
goto error;
+ if (virDomainParseMemory("./memoryBacking/hugepages/pagesize[1]", ctxt,
+ &def->mem.page_size, false) < 0)
+ goto error;
+
n = virXPathULong("string(./vcpu[1])", ctxt, &count);
if (n == -2) {
virReportError(VIR_ERR_XML_ERROR, "%s",
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index d8f2e49..03a900d 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1984,6 +1984,7 @@ struct _virDomainDef {
unsigned long long soft_limit; /* in kibibytes */
unsigned long long min_guarantee; /* in kibibytes */
unsigned long long swap_hard_limit; /* in kibibytes */
+ unsigned long long page_size; /* in kibibytes */
} mem;
unsigned short vcpus;
unsigned short maxvcpus;
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 8bcd98e..cd5e1c8 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -3570,6 +3570,33 @@ cleanup:
return ret;
}
+#ifdef __linux__
+
+#include <sys/vfs.h>
+
+#define HUGETLBFS_MAGIC 0x958458f6
+
+static long gethugepagesize(const char *path)
+{
+ struct statfs fs;
+ int ret;
+
+ do {
+ ret = statfs(path, &fs);
+ } while (ret != 0 && errno == EINTR);
+
+ if (ret != 0) {
+ perror(path);
+ return 0;
+ }
+
+ if (fs.f_type != HUGETLBFS_MAGIC)
+ return 0;
+
+ return fs.f_bsize;
+}
+#endif
+
int qemuProcessStart(virConnectPtr conn,
virQEMUDriverPtr driver,
@@ -3712,6 +3739,31 @@ int qemuProcessStart(virConnectPtr conn,
"%s", _("Unable to set huge path in security
driver"));
goto cleanup;
}
+
+ if (vm->def->mem.page_size) {
+#ifdef __linux__
+ unsigned long hpagesize = gethugepagesize(cfg->hugepagePath);
+
+ if (!hpagesize) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ "%s", _("Unable to stat hugepage
path"));
+ goto cleanup;
+ }
+
+ hpagesize /= 1024;
+
+ if (hpagesize < vm->def->mem.page_size) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Error: hugetlbfs page size=%ld < pagesize=%lld"),
+ hpagesize, vm->def->mem.page_size);
+ goto cleanup;
+ }
+#else
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ "%s", _("pagesize option unsupported"));
+ goto cleanup;
+#endif
+ }
}
/* Ensure no historical cgroup for this VM is lying around bogus