Re: [PATCH V2 1/4] conf: Add support for specifying CPU max physical address size

From: Dario Faggioli <dfaggioli(a)suse.com&gt; This patch introduces the <maxphysaddr mode='passthrough'/> <maxphysaddr mode='emulate' bits='42'/> sub element of /domain/cpu, which allows specifying the guest virtual CPU address size. This can be useful if the guest needs to have a large amount of memory. If mode='passthrough', the virtual CPU will have the same number of address bits as the host. If mode='emulate', the mandatory bits attribute specifies the number of address bits. Signed-off-by: Dario Faggioli <dfaggioli(a)suse.com&gt; Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; --- docs/formatdomain.rst | 23 ++++++++ src/conf/cpu_conf.c | 54 +++++++++++++++++++ src/conf/cpu_conf.h | 17 ++++++ src/conf/schemas/cputypes.rng | 19 +++++++ src/libvirt_private.syms | 2 + .../cpu-phys-bits-emulate.xml | 20 +++++++ .../cpu-phys-bits-passthrough.xml | 20 +++++++ tests/genericxml2xmltest.c | 3 ++ 8 files changed, 158 insertions(+) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 1ed969ac3e..adfdd7b7a5 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -1336,6 +1336,7 @@ following collection of elements. :since:`Since 0.7.5` <vendor>Intel</vendor> <topology sockets='1' dies='1' cores='2' threads='1'/> <cache level='3' mode='emulate'/> + <maxphysaddr mode='emulate' bits='42'> <feature policy='disable' name='lahf_lm'/> </cpu> ... @@ -1352,6 +1353,7 @@ following collection of elements. :since:`Since 0.7.5` <cpu mode='host-passthrough' migratable='off'> <cache mode='passthrough'/> + <maxphysaddr mode='passthrough'> <feature policy='disable' name='lahf_lm'/> ... @@ -1600,6 +1602,27 @@ In case no restrictions need to be put on CPU model and its features, a simpler The virtual CPU will report no CPU cache of the specified level (or no cache at all if the ``level`` attribute is missing). +``maxphysaddr`` + :since:`Since 8.7.0` the ``maxphysaddr`` element describes the virtual CPU + address size in bits. The hypervisor default is used if the element is missing. + + ``mode`` + This mandatory attribute specifies how the address size is presented. The + follow modes are supported: + + ``passthrough`` + The number of physical address bits reported by the host CPU will be + passed through to the virtual CPUs + ``emulate`` + The hypervisor will define a specific value for the number of bits + of physical addresses via the ``bits`` attribute, which is mandatory. + The number of bits cannot exceed the number of physical address bits + supported by the hypervisor. + + ``bits`` + The ``bits`` attribute is mandatory if the ``mode`` attribute is set to + ``emulate`` and specifies the virtual CPU address size in bits. + Guest NUMA topology can be specified using the ``numa`` element. :since:`Since 0.9.8` diff --git a/src/conf/cpu_conf.c b/src/conf/cpu_conf.c index 8d80bbd842..e31c4ab467 100644 --- a/src/conf/cpu_conf.c +++ b/src/conf/cpu_conf.c @@ -82,6 +82,12 @@ VIR_ENUM_IMPL(virCPUCacheMode, "disable", ); +VIR_ENUM_IMPL(virCPUMaxPhysAddrMode, + VIR_CPU_MAX_PHYS_ADDR_MODE_LAST, + "emulate", + "passthrough", +); + virCPUDef *virCPUDefNew(void) { @@ -127,6 +133,7 @@ virCPUDefFree(virCPUDef *def) if (g_atomic_int_dec_and_test(&def->refs)) { virCPUDefFreeModel(def); g_free(def->cache); + g_free(def->addr); g_free(def->tsc); g_free(def); } @@ -252,6 +259,11 @@ virCPUDefCopyWithoutModel(const virCPUDef *cpu) *copy->cache = *cpu->cache; } + if (cpu->addr) { + copy->addr = g_new0(virCPUMaxPhysAddrDef, 1); + *copy->addr = *cpu->addr; + } + if (cpu->tsc) { copy->tsc = g_new0(virHostCPUTscInfo, 1); *copy->tsc = *cpu->tsc; @@ -644,6 +656,39 @@ virCPUDefParseXML(xmlXPathContextPtr ctxt, def->cache->mode = mode; } + if (virXPathInt("count(./maxphysaddr)", ctxt, &n) < 0) { + return -1; + } else if (n > 1) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("at most one CPU maximum physical address bits " + "element may be specified")); + return -1; + } else if (n == 1) { + g_autofree char *strmode = NULL; + int mode; + int bits = -1; + + if (!(strmode = virXPathString("string(./maxphysaddr[1]/@mode)", ctxt)) || + (mode = virCPUMaxPhysAddrModeTypeFromString(strmode)) < 0) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("missing or invalid CPU maximum physical " + "address bits mode")); + return -1; + } + + if (virXPathBoolean("boolean(./maxphysaddr[1]/@bits)", ctxt) == 1 && + (virXPathInt("string(./maxphysaddr[1]/@bits)", ctxt, &bits) < 0 || + bits < 0)) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("CPU maximum physical address bits < 0")); + return -1; + }