[Xen-devel] [PATCH v6 4/5] 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 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. If it's enabled, then
the domain receives a copy of HVM_max vmx policy with allowed CR4 bits
adjusted by CPUID policy.

Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
v5 --> v6:
- Updated recalculate_msr_policy() comment and commit message
- Added Reviewed-by
---
 xen/arch/x86/domctl.c     |  1 +
 xen/arch/x86/msr.c        | 35 +++++++++++++++++++++++++++++++++++
 xen/include/asm-x86/msr.h |  3 +++
 3 files changed, 39 insertions(+)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 8fbbf3aeb3..5bde1a22b7 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -125,6 +125,7 @@ static int update_domain_cpuid_info(struct domain *d,
     }
 
     recalculate_cpuid_policy(d);
+    recalculate_msr_policy(d);
 
     switch ( ctl->input[0] )
     {
diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index 01a5b52f95..26d987098b 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>
 
 DEFINE_PER_CPU(uint32_t, tsc_aux);
 
@@ -283,6 +284,39 @@ void __init init_guest_msr_policy(void)
     calculate_pv_max_policy();
 }
 
+static void vmx_copy_policy(const struct msr_domain_policy *src,
+                                  struct msr_domain_policy *dst)
+{
+    memcpy(dst->vmx.raw, src->vmx.raw, sizeof(dst->vmx.raw));
+    dst->vmx_procbased_ctls2.raw = src->vmx_procbased_ctls2.raw;
+    dst->vmx_ept_vpid_cap.raw = src->vmx_ept_vpid_cap.raw;
+    memcpy(dst->vmx_true_ctls.raw, src->vmx_true_ctls.raw,
+           sizeof(dst->vmx_true_ctls.raw));
+    dst->vmx_vmfunc.raw = src->vmx_vmfunc.raw;
+}
+
+static void recalculate_vmx_msr_policy(struct domain *d)
+{
+    struct msr_domain_policy *dp = d->arch.msr;
+
+    if ( !nestedhvm_enabled(d) || !d->arch.cpuid->basic.vmx )
+    {
+        vmx_clear_policy(dp);
+
+        return;
+    }
+
+    vmx_copy_policy(&hvm_max_msr_domain_policy, dp);
+
+    /* Get allowed CR4 bits from CPUID policy */
+    dp->vmx.cr4_fixed1.allowed_1.raw = hvm_cr4_guest_valid_bits(d, false);
+}
+
+void recalculate_msr_policy(struct domain *d)
+{
+    recalculate_vmx_msr_policy(d);
+}
+
 int init_domain_msr_policy(struct domain *d)
 {
     struct msr_domain_policy *dp;
@@ -303,6 +337,7 @@ int init_domain_msr_policy(struct domain *d)
     }
 
     d->arch.msr = dp;
+    recalculate_msr_policy(d);
 
     return 0;
 }
diff --git a/xen/include/asm-x86/msr.h b/xen/include/asm-x86/msr.h
index 5fdf82860e..41433fea94 100644
--- a/xen/include/asm-x86/msr.h
+++ b/xen/include/asm-x86/msr.h
@@ -641,6 +641,9 @@ 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);
 
+/* Updates availability of MSRs based on CPUID policy */
+void recalculate_msr_policy(struct domain *d);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_MSR_H */
-- 
2.14.1


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