[Xen-devel] [PATCH v4 6/7] x86/msr: update domain policy on CPUID policy changes

[Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>]

Availability of some MSRs depends on certain CPUID bits. Add function
recalculate_domain_msr_policy() which updates availability of per-domain
MSRs based on current domain's CPUID policy. This function is called
when CPUID policy is changed from a toolstack.

Add recalculate_domain_vmx_msr_policy() which changes availability of
VMX MSRs based on domain's nested virt settings. Unavailable MSRs are
zeroed which allows checking availability bits in them directly without
preliminary checks (e.g. cpuid->basic.vmx, activate_secondary_controls,
enable_ept).

Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
---
 xen/arch/x86/domctl.c     |  1 +
 xen/arch/x86/msr.c        | 55 +++++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-x86/msr.h |  3 +++
 3 files changed, 59 insertions(+)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 80b4df9ec9..334c67d261 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -124,6 +124,7 @@ static int update_domain_cpuid_info(struct domain *d,
     }
 
     recalculate_cpuid_policy(d);
+    recalculate_domain_msr_policy(d);
 
     switch ( ctl->input[0] )
     {
diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index ff270befbb..9ea7447de3 100644
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -23,6 +23,7 @@
 #include <xen/lib.h>
 #include <xen/sched.h>
 #include <asm/msr.h>
+#include <asm/hvm/nestedhvm.h>
 
 struct msr_domain_policy __read_mostly     raw_msr_domain_policy,
                          __read_mostly    host_msr_domain_policy,
@@ -257,6 +258,59 @@ void __init init_guest_msr_policy(void)
     calculate_pv_max_policy();
 }
 
+static void recalculate_domain_vmx_msr_policy(struct domain *d)
+{
+    struct msr_domain_policy *dp = d->arch.msr;
+
+    if ( !nestedhvm_enabled(d) || !d->arch.cpuid->basic.vmx )
+    {
+        memset(dp->vmx.raw, 0, sizeof(dp->vmx.raw));
+        dp->vmx_procbased_ctls2.raw = 0;
+        dp->vmx_ept_vpid_cap.raw = 0;
+        memset(dp->vmx_true_ctls.raw, 0, sizeof(dp->vmx_true_ctls.raw));
+        dp->vmx_vmfunc.raw = 0;
+    }
+    else
+    {
+        memcpy(dp->vmx.raw, hvm_max_msr_domain_policy.vmx.raw,
+               sizeof(dp->vmx.raw));
+        /* Get allowed CR4 bits from CPUID policy */
+        dp->vmx.cr4_fixed1.raw = hvm_cr4_guest_valid_bits(d, false);
+
+        if ( dp->vmx.procbased_ctls.allowed_1.activate_secondary_controls )
+        {
+            dp->vmx_procbased_ctls2.raw =
+                hvm_max_msr_domain_policy.vmx_procbased_ctls2.raw;
+
+            if ( dp->vmx_procbased_ctls2.allowed_1.enable_ept ||
+                 dp->vmx_procbased_ctls2.allowed_1.enable_vpid )
+                dp->vmx_ept_vpid_cap.raw =
+                    hvm_max_msr_domain_policy.vmx_ept_vpid_cap.raw;
+            else
+                dp->vmx_ept_vpid_cap.raw = 0;
+        }
+        else
+        {
+            dp->vmx_procbased_ctls2.raw = 0;
+            dp->vmx_ept_vpid_cap.raw = 0;
+        }
+
+        if ( dp->vmx.basic.default1_zero )
+            memcpy(dp->vmx_true_ctls.raw,
+                   hvm_max_msr_domain_policy.vmx_true_ctls.raw,
+                   sizeof(dp->vmx_true_ctls.raw));
+        else
+            memset(dp->vmx_true_ctls.raw, 0, sizeof(dp->vmx_true_ctls.raw));
+
+        dp->vmx_vmfunc.raw = 0;
+    }
+}
+
+void recalculate_domain_msr_policy(struct domain *d)
+{
+    recalculate_domain_vmx_msr_policy(d);
+}
+
 int init_domain_msr_policy(struct domain *d)
 {
     struct msr_domain_policy *dp;
@@ -277,6 +331,7 @@ int init_domain_msr_policy(struct domain *d)
     }
 
     d->arch.msr = dp;
+    recalculate_domain_msr_policy(d);
 
     return 0;
 }
diff --git a/xen/include/asm-x86/msr.h b/xen/include/asm-x86/msr.h
index 150000551f..f19e113612 100644
--- a/xen/include/asm-x86/msr.h
+++ b/xen/include/asm-x86/msr.h
@@ -608,6 +608,9 @@ int init_vcpu_msr_policy(struct vcpu *v);
 int guest_rdmsr(const struct vcpu *v, uint32_t msr, uint64_t *val);
 int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t val);
 
+/* Update availability of per-domain MSRs based on CPUID policy */
+void recalculate_domain_msr_policy(struct domain *d);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_MSR_H */
-- 
2.11.0


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