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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 3/8] x86/domctl: Implement XEN_DOMCTL_set_cpumsr_policy
This hypercall allows the toolstack to present one combined CPUID and MSR
policy for a domain, which can be audited in one go by Xen, which is necessary
for correctness of the auditing.
Reuse the existing set_cpuid XSM access vector, as this is logically the same
operation.
As x86_cpu_policies_are_compatible() is still only a stub, retain the call to
recalculate_cpuid_policy() to discard unsafe toolstack settings.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
tools/libxc/include/xenctrl.h | 5 +++
tools/libxc/xc_cpuid_x86.c | 49 +++++++++++++++++++++++
xen/arch/x86/domctl.c | 80 +++++++++++++++++++++++++++++++++++++
xen/include/public/domctl.h | 15 +++++--
xen/xsm/flask/hooks.c | 1 +
xen/xsm/flask/policy/access_vectors | 1 +
6 files changed, 147 insertions(+), 4 deletions(-)
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 7559e1bc69..e47778535d 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -2530,6 +2530,11 @@ int xc_get_system_cpu_policy(xc_interface *xch, uint32_t
index,
int xc_get_domain_cpu_policy(xc_interface *xch, uint32_t domid,
uint32_t *nr_leaves, xen_cpuid_leaf_t *leaves,
uint32_t *nr_msrs, xen_msr_entry_t *msrs);
+int xc_set_domain_cpu_policy(xc_interface *xch, uint32_t domid,
+ uint32_t nr_leaves, xen_cpuid_leaf_t *leaves,
+ uint32_t nr_msrs, xen_msr_entry_t *msrs,
+ uint32_t *err_leaf_p, uint32_t *err_subleaf_p,
+ uint32_t *err_msr_idx_p);
uint32_t xc_get_cpu_featureset_size(void);
diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index b829336082..33b9e9fc85 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -229,6 +229,55 @@ int xc_get_domain_cpu_policy(xc_interface *xch, uint32_t
domid,
return ret;
}
+int xc_set_domain_cpu_policy(xc_interface *xch, uint32_t domid,
+ uint32_t nr_leaves, xen_cpuid_leaf_t *leaves,
+ uint32_t nr_msrs, xen_msr_entry_t *msrs,
+ uint32_t *err_leaf_p, uint32_t *err_subleaf_p,
+ uint32_t *err_msr_idx_p)
+{
+ DECLARE_DOMCTL;
+ DECLARE_HYPERCALL_BOUNCE(leaves,
+ nr_leaves * sizeof(*leaves),
+ XC_HYPERCALL_BUFFER_BOUNCE_IN);
+ DECLARE_HYPERCALL_BOUNCE(msrs,
+ nr_msrs * sizeof(*msrs),
+ XC_HYPERCALL_BUFFER_BOUNCE_IN);
+ int ret;
+
+ if ( xc_hypercall_bounce_pre(xch, leaves) )
+ return -1;
+
+ if ( xc_hypercall_bounce_pre(xch, msrs) )
+ return -1;
+
+ domctl.cmd = XEN_DOMCTL_set_cpu_policy;
+ domctl.domain = domid;
+ domctl.u.cpu_policy.nr_leaves = nr_leaves;
+ set_xen_guest_handle(domctl.u.cpu_policy.cpuid_policy, leaves);
+ domctl.u.cpu_policy.nr_msrs = nr_msrs;
+ set_xen_guest_handle(domctl.u.cpu_policy.msr_policy, msrs);
+ domctl.u.cpu_policy.err_leaf = ~0;
+ domctl.u.cpu_policy.err_subleaf = ~0;
+ domctl.u.cpu_policy.err_msr_idx = ~0;
+
+ ret = do_domctl(xch, &domctl);
+
+ xc_hypercall_bounce_post(xch, leaves);
+ xc_hypercall_bounce_post(xch, msrs);
+
+ if ( ret )
+ {
+ if ( err_leaf_p )
+ *err_leaf_p = domctl.u.cpu_policy.err_leaf;
+ if ( err_subleaf_p )
+ *err_subleaf_p = domctl.u.cpu_policy.err_subleaf;
+ if ( err_msr_idx_p )
+ *err_msr_idx_p = domctl.u.cpu_policy.err_msr_idx;
+ }
+
+ return ret;
+}
+
struct cpuid_domain_info
{
unsigned int vendor; /* X86_VENDOR_* */
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index d15ae066c3..99bc2fb10d 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -294,6 +294,65 @@ static int update_domain_cpuid_info(struct domain *d,
return 0;
}
+static int update_domain_cpu_policy(struct domain *d,
+ xen_domctl_cpu_policy_t *xdpc)
+{
+ struct cpu_policy new = {};
+ const struct cpu_policy *sys = is_pv_domain(d)
+ ? &system_policies[XEN_SYSCTL_cpu_policy_pv_max]
+ : &system_policies[XEN_SYSCTL_cpu_policy_hvm_max];
+ struct cpu_policy_errors err = INIT_CPU_POLICY_ERRORS;
+ int ret = -ENOMEM;
+
+ /* Start by copying the domain's existing policies. */
+ if ( !(new.cpuid = xmemdup(d->arch.cpuid)) ||
+ !(new.msr = xmemdup(d->arch.msr)) )
+ goto out;
+
+ /* Merge the toolstack provided data. */
+ if ( (ret = x86_cpuid_copy_from_buffer(
+ new.cpuid, xdpc->cpuid_policy, xdpc->nr_leaves,
+ &err.leaf, &err.subleaf)) ||
+ (ret = x86_msr_copy_from_buffer(
+ new.msr, xdpc->msr_policy, xdpc->nr_msrs, &err.msr)) )
+ goto out;
+
+ /* Trim any newly-stale out-of-range leaves. */
+ x86_cpuid_policy_clear_out_of_range_leaves(new.cpuid);
+
+ /* Audit the combined dataset. */
+ ret = x86_cpu_policies_are_compatible(sys, &new, &err);
+ if ( ret )
+ goto out;
+
+ /*
+ * Audit was successful. Replace existing policies, leaving the old
+ * policies to be freed.
+ */
+ SWAP(new.cpuid, d->arch.cpuid);
+ SWAP(new.msr, d->arch.msr);
+
+ /* TODO: Drop when x86_cpu_policies_are_compatible() is completed. */
+ recalculate_cpuid_policy(d);
+
+ /* Recalculate relevant dom/vcpu state now the policy has changed. */
+ domain_cpu_policy_changed(d);
+
+ out:
+ /* Free whichever cpuid/msr structs are not installed in struct domain. */
+ xfree(new.cpuid);
+ xfree(new.msr);
+
+ if ( ret )
+ {
+ xdpc->err_leaf = err.leaf;
+ xdpc->err_subleaf = err.subleaf;
+ xdpc->err_msr_idx = err.msr;
+ }
+
+ return ret;
+}
+
static int vcpu_set_vmce(struct vcpu *v,
const struct xen_domctl_ext_vcpucontext *evc)
{
@@ -1476,6 +1535,27 @@ long arch_do_domctl(
copyback = true;
break;
+ case XEN_DOMCTL_set_cpu_policy:
+ if ( d == currd ) /* No domain_pause() */
+ {
+ ret = -EINVAL;
+ break;
+ }
+
+ domain_pause(d);
+
+ if ( d->creation_finished )
+ ret = -EEXIST; /* No changing once the domain is running. */
+ else
+ {
+ ret = update_domain_cpu_policy(d, &domctl->u.cpu_policy);
+ if ( ret ) /* Copy domctl->u.cpu_policy.err_* to guest. */
+ copyback = true;
+ }
+
+ domain_unpause(d);
+ break;
+
default:
ret = iommu_do_domctl(domctl, d, u_domctl);
break;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 77f546cbb8..0471d3c680 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -658,17 +658,23 @@ struct xen_domctl_cpuid {
};
/*
- * XEN_DOMCTL_get_cpu_policy (x86 specific)
+ * XEN_DOMCTL_{get,set}_cpu_policy (x86 specific)
*
- * Query the CPUID and MSR policies for a specific domain.
+ * Query or set the CPUID and MSR policies for a specific domain.
*/
struct xen_domctl_cpu_policy {
uint32_t nr_leaves; /* IN/OUT: Number of leaves in/written to
* 'cpuid_policy'. */
uint32_t nr_msrs; /* IN/OUT: Number of MSRs in/written to
* 'msr_domain_policy' */
- XEN_GUEST_HANDLE_64(xen_cpuid_leaf_t) cpuid_policy; /* OUT */
- XEN_GUEST_HANDLE_64(xen_msr_entry_t) msr_policy; /* OUT */
+ XEN_GUEST_HANDLE_64(xen_cpuid_leaf_t) cpuid_policy; /* IN/OUT */
+ XEN_GUEST_HANDLE_64(xen_msr_entry_t) msr_policy; /* IN/OUT */
+ uint32_t err_leaf, err_subleaf; /* OUT, set_policy only. If not ~0,
+ * indicates the leaf/subleaf which
+ * auditing objected to. */
+ uint32_t err_msr_idx; /* OUT, set_policy only. If not ~0,
+ * indicates the MSR idx which
+ * auditing objected to. */
};
typedef struct xen_domctl_cpu_policy xen_domctl_cpu_policy_t;
DEFINE_XEN_GUEST_HANDLE(xen_domctl_cpu_policy_t);
@@ -1193,6 +1199,7 @@ struct xen_domctl {
/* #define XEN_DOMCTL_set_gnttab_limits 80 - Moved into
XEN_DOMCTL_createdomain */
#define XEN_DOMCTL_vuart_op 81
#define XEN_DOMCTL_get_cpu_policy 82
+#define XEN_DOMCTL_set_cpu_policy 83
#define XEN_DOMCTL_gdbsx_guestmemio 1000
#define XEN_DOMCTL_gdbsx_pausevcpu 1001
#define XEN_DOMCTL_gdbsx_unpausevcpu 1002
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 6800f2d9a0..b23772786a 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -715,6 +715,7 @@ static int flask_domctl(struct domain *d, int cmd)
case XEN_DOMCTL_set_virq_handler:
return current_has_perm(d, SECCLASS_DOMAIN, DOMAIN__SET_VIRQ_HANDLER);
+ case XEN_DOMCTL_set_cpu_policy:
case XEN_DOMCTL_set_cpuid:
return current_has_perm(d, SECCLASS_DOMAIN2, DOMAIN2__SET_CPUID);
diff --git a/xen/xsm/flask/policy/access_vectors
b/xen/xsm/flask/policy/access_vectors
index 76f3d60ddd..6f3f9493f8 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -207,6 +207,7 @@ class domain2
# source = the domain making the hypercall
# target = the new target domain
set_as_target
+# XEN_DOMCTL_set_cpu_policy
# XEN_DOMCTL_set_cpuid
set_cpuid
# XEN_DOMCTL_gettscinfo
--
2.11.0
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