Hi Luca,
On 24/04/2023 07:02, Luca Fancellu wrote:
Add sve_vl field to arch_domain and xen_arch_domainconfig struct,
to allow the domain to have an information about the SVE feature
and the number of SVE register bits that are allowed for this
domain.
sve_vl field is the vector length in bits divided by 128, this
allows to use less space in the structures.
The field is used also to allow or forbid a domain to use SVE,
because a value equal to zero means the guest is not allowed to
use the feature.
Check that the requested vector length is lower or equal to the
platform supported vector length, otherwise fail on domain
creation.
Check that only 64 bit domains have SVE enabled, otherwise fail.
Bump the XEN_DOMCTL_INTERFACE_VERSION because of the new field
in struct xen_arch_domainconfig.
The domctl interface version was bumped this week (see bdb1184d4f
"domctl: bump interface version"). So this will not be necessary.
Signed-off-by: Luca Fancellu <luca.fance...@arm.com>
---
Changes from v5:
- Update commit message stating the interface ver. bump (Bertrand)
- in struct arch_domain, protect sve_vl with CONFIG_ARM64_SVE,
given the change, move also is_sve_domain() where it's protected
inside sve.h and create a stub when the macro is not defined,
protect the usage of sve_vl where needed.
(Julien)
- Add a check for 32 bit guest running on top of 64 bit host that
have sve parameter enabled to stop the domain creation, added in
construct_domain() of domain_build.c and subarch_do_domctl of
domctl.c. (Julien)
Changes from v4:
- Return 0 in get_sys_vl_len() if sve is not supported, code style fix,
removed else if since the conditions can't fallthrough, removed not
needed condition checking for VL bits validity because it's already
covered, so delete is_vl_valid() function. (Jan)
Changes from v3:
- don't use fixed types when not needed, use encoded value also in
arch_domain so rename sve_vl_bits in sve_vl. (Jan)
- rename domainconfig_decode_vl to sve_decode_vl because it will now
be used also to decode from arch_domain value
- change sve_vl from uint16_t to uint8_t and move it after "type" field
to optimize space.
Changes from v2:
- rename field in xen_arch_domainconfig from "sve_vl_bits" to
"sve_vl" and use the implicit padding after gic_version to
store it, now this field is the VL/128. (Jan)
- Created domainconfig_decode_vl() function to decode the sve_vl
field and use it as plain bits value inside arch_domain.
- Changed commit message reflecting the changes
Changes from v1:
- no changes
Changes from RFC:
- restore zcr_el2 in sve_restore_state, that will be introduced
later in this serie, so remove zcr_el2 related code from this
patch and move everything to the later patch (Julien)
- add explicit padding into struct xen_arch_domainconfig (Julien)
- Don't lower down the vector length, just fail to create the
domain. (Julien)
---
xen/arch/arm/arm64/domctl.c | 4 ++++
xen/arch/arm/arm64/sve.c | 12 ++++++++++++
xen/arch/arm/domain.c | 29 ++++++++++++++++++++++++++++
xen/arch/arm/domain_build.c | 7 +++++++
xen/arch/arm/include/asm/arm64/sve.h | 16 +++++++++++++++
xen/arch/arm/include/asm/domain.h | 5 +++++
xen/include/public/arch-arm.h | 2 ++
xen/include/public/domctl.h | 2 +-
8 files changed, 76 insertions(+), 1 deletion(-)
diff --git a/xen/arch/arm/arm64/domctl.c b/xen/arch/arm/arm64/domctl.c
index 0de89b42c448..14fc622e9956 100644
--- a/xen/arch/arm/arm64/domctl.c
+++ b/xen/arch/arm/arm64/domctl.c
@@ -10,6 +10,7 @@
#include <xen/sched.h>
#include <xen/hypercall.h>
#include <public/domctl.h>
+#include <asm/arm64/sve.h>
#include <asm/cpufeature.h>
static long switch_mode(struct domain *d, enum domain_type type)
@@ -43,6 +44,9 @@ long subarch_do_domctl(struct xen_domctl *domctl, struct
domain *d,
case 32:
if ( !cpu_has_el1_32 )
return -EINVAL;
+ /* SVE is not supported for 32 bit domain */
+ if ( is_sve_domain(d) )
+ return -EINVAL;
return switch_mode(d, DOMAIN_32BIT);
case 64:
return switch_mode(d, DOMAIN_64BIT);
diff --git a/xen/arch/arm/arm64/sve.c b/xen/arch/arm/arm64/sve.c
index 6f3fb368c59b..86a5e617bfca 100644
--- a/xen/arch/arm/arm64/sve.c
+++ b/xen/arch/arm/arm64/sve.c
@@ -8,6 +8,7 @@
#include <xen/types.h>
#include <asm/arm64/sve.h>
#include <asm/arm64/sysregs.h>
+#include <asm/cpufeature.h>
#include <asm/processor.h>
#include <asm/system.h>
@@ -48,3 +49,14 @@ register_t vl_to_zcr(unsigned int vl)
ASSERT(vl > 0);
return ((vl / SVE_VL_MULTIPLE_VAL) - 1U) & ZCR_ELx_LEN_MASK;
}
+
+/* Get the system sanitized value for VL in bits */
+unsigned int get_sys_vl_len(void)
+{
+ if ( !cpu_has_sve )
+ return 0;
+
+ /* ZCR_ELx len field is ((len+1) * 128) = vector bits length */
NIT: Please add a space before and after '+'.
+ return ((system_cpuinfo.zcr64.bits[0] & ZCR_ELx_LEN_MASK) + 1U) *
+ SVE_VL_MULTIPLE_VAL;
+}
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 0350d8c61ed8..143359d0f313 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -13,6 +13,7 @@
#include <xen/wait.h>
#include <asm/alternative.h>
+#include <asm/arm64/sve.h>
#include <asm/cpuerrata.h>
#include <asm/cpufeature.h>
#include <asm/current.h>
@@ -550,6 +551,8 @@ int arch_vcpu_create(struct vcpu *v)
v->arch.vmpidr = MPIDR_SMP | vcpuid_to_vaffinity(v->vcpu_id);
v->arch.cptr_el2 = get_default_cptr_flags();
+ if ( is_sve_domain(v->domain) )
+ v->arch.cptr_el2 &= ~HCPTR_CP(8);
v->arch.hcr_el2 = get_default_hcr_flags();
@@ -594,6 +597,7 @@ int arch_sanitise_domain_config(struct xen_domctl_createdomain *config)
unsigned int max_vcpus;
unsigned int flags_required = (XEN_DOMCTL_CDF_hvm | XEN_DOMCTL_CDF_hap);
unsigned int flags_optional = (XEN_DOMCTL_CDF_iommu |
XEN_DOMCTL_CDF_vpmu);
+ unsigned int sve_vl_bits = sve_decode_vl(config->arch.sve_vl);
if ( (config->flags & ~flags_optional) != flags_required )
{
@@ -602,6 +606,26 @@ int arch_sanitise_domain_config(struct
xen_domctl_createdomain *config)
return -EINVAL;
}
+ /* Check feature flags */
+ if ( sve_vl_bits > 0 )
+ {
+ unsigned int zcr_max_bits = get_sys_vl_len();
+
+ if ( !zcr_max_bits )
+ {
+ dprintk(XENLOG_INFO, "SVE is unsupported on this machine.\n");
+ return -EINVAL;
+ }
+
+ if ( sve_vl_bits > zcr_max_bits )
+ {
+ dprintk(XENLOG_INFO,
+ "Requested SVE vector length (%u) > supported length
(%u)\n",
+ sve_vl_bits, zcr_max_bits);
+ return -EINVAL;
+ }
+ }
+
/* The P2M table must always be shared between the CPU and the IOMMU */
if ( config->iommu_opts & XEN_DOMCTL_IOMMU_no_sharept )
{
@@ -744,6 +768,11 @@ int arch_domain_create(struct domain *d,
if ( (rc = domain_vpci_init(d)) != 0 )
goto fail;
+#ifdef CONFIG_ARM64_SVE
+ /* Copy the encoded vector length sve_vl from the domain configuration */
+ d->arch.sve_vl = config->arch.sve_vl;
+#endif
+
return 0;
fail:
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index f80fdd1af206..ffabe567ac3f 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -26,6 +26,7 @@
#include <asm/platform.h>
#include <asm/psci.h>
#include <asm/setup.h>
+#include <asm/arm64/sve.h>
#include <asm/cpufeature.h>
#include <asm/domain_build.h>
#include <xen/event.h>
@@ -3674,6 +3675,12 @@ static int __init construct_domain(struct domain *d,
struct kernel_info *kinfo)
return -EINVAL;
}
+ if ( is_sve_domain(d) && (kinfo->type == DOMAIN_32BIT) )
+ {
+ printk("SVE is not available for 32-bit domain\n");
+ return -EINVAL;
+ }
+
if ( is_64bit_domain(d) )
vcpu_switch_to_aarch64_mode(v);
diff --git a/xen/arch/arm/include/asm/arm64/sve.h b/xen/arch/arm/include/asm/arm64/sve.h
index 144d2b1cc485..730c3fb5a9c8 100644
--- a/xen/arch/arm/include/asm/arm64/sve.h
+++ b/xen/arch/arm/include/asm/arm64/sve.h
@@ -13,13 +13,24 @@
/* Vector length must be multiple of 128 */
#define SVE_VL_MULTIPLE_VAL (128U)
+static inline unsigned int sve_decode_vl(unsigned int sve_vl)
+{
+ /* SVE vector length is stored as VL/128 in xen_arch_domainconfig */
+ return sve_vl * SVE_VL_MULTIPLE_VAL;
+}
+
#ifdef CONFIG_ARM64_SVE
+#define is_sve_domain(d) ((d)->arch.sve_vl > 0)
+
register_t compute_max_zcr(void);
register_t vl_to_zcr(unsigned int vl);
+unsigned int get_sys_vl_len(void);
#else /* !CONFIG_ARM64_SVE */
+#define is_sve_domain(d) (0)
You want to use (d, 0) so 'd' is still evaluated when !SVE is not
enabled. An alternative is to provide a static line helper.
+
static inline register_t compute_max_zcr(void)
{
return 0;
@@ -30,6 +41,11 @@ static inline register_t vl_to_zcr(unsigned int vl)
return 0;
}
+static inline unsigned int get_sys_vl_len(void)
+{
+ return 0;
+}
+
#endif /* CONFIG_ARM64_SVE */
#endif /* _ARM_ARM64_SVE_H */
diff --git a/xen/arch/arm/include/asm/domain.h
b/xen/arch/arm/include/asm/domain.h
index e776ee704b7d..331da0f3bcc3 100644
--- a/xen/arch/arm/include/asm/domain.h
+++ b/xen/arch/arm/include/asm/domain.h
@@ -67,6 +67,11 @@ struct arch_domain
enum domain_type type;
#endif
+#ifdef CONFIG_ARM64_SVE
+ /* max SVE encoded vector length */
+ uint8_t sve_vl;
+#endif
+
/* Virtual MMU */
struct p2m_domain p2m;
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index 1528ced5097a..38311f559581 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -300,6 +300,8 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_guest_context_t);
struct xen_arch_domainconfig {
/* IN/OUT */
uint8_t gic_version;
+ /* IN - Contains SVE vector length divided by 128 */
+ uint8_t sve_vl;
/* IN */
uint16_t tee_type;
/* IN */
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 529801c89ba3..e2e22cb534d6 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -21,7 +21,7 @@
#include "hvm/save.h"
#include "memory.h"
-#define XEN_DOMCTL_INTERFACE_VERSION 0x00000015
+#define XEN_DOMCTL_INTERFACE_VERSION 0x00000016
/*
* NB. xen_domctl.domain is an IN/OUT parameter for this operation.
Cheers,
--
Julien Grall
