[xen staging] VMX: convert vmx_basic_msr

[patchbot@xxxxxxx]

commit f7a31ac57281abc95159872e0b006b48b52efe98
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Mar 6 13:57:21 2025 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Mar 6 13:57:21 2025 +0100

    VMX: convert vmx_basic_msr
    
    ... to a struct field, which is then going to be accompanied by other
    capability/control data presently living in individual variables. As
    this structure isn't supposed to be altered post-boot, put it in
    .data.ro_after_init right away.
    
    Suggested-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c             | 12 ++++++------
 xen/arch/x86/hvm/vmx/vvmx.c             |  6 +++---
 xen/arch/x86/include/asm/hvm/vmx/vmcs.h |  9 +++++++--
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 0622ef40db..bd0d931063 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -163,6 +163,7 @@ static int cf_check parse_ept_param_runtime(const char *s)
 #endif
 
 /* Dynamic (run-time adjusted) execution control flags. */
+struct vmx_caps __ro_after_init vmx_caps;
 u32 vmx_pin_based_exec_control __read_mostly;
 u32 vmx_cpu_based_exec_control __read_mostly;
 u32 vmx_secondary_exec_control __read_mostly;
@@ -177,8 +178,7 @@ static DEFINE_PER_CPU(paddr_t, current_vmcs);
 static DEFINE_PER_CPU(struct list_head, active_vmcs_list);
 DEFINE_PER_CPU(bool, vmxon);
 
-#define vmcs_revision_id (vmx_basic_msr & VMX_BASIC_REVISION_MASK)
-u64 __read_mostly vmx_basic_msr;
+#define vmcs_revision_id (vmx_caps.basic_msr & VMX_BASIC_REVISION_MASK)
 
 static void __init vmx_display_features(void)
 {
@@ -510,8 +510,8 @@ static int vmx_init_vmcs_config(bool bsp)
         vmx_ept_vpid_cap           = _vmx_ept_vpid_cap;
         vmx_vmexit_control         = _vmx_vmexit_control;
         vmx_vmentry_control        = _vmx_vmentry_control;
-        vmx_basic_msr              = ((u64)vmx_basic_msr_high << 32) |
-                                     vmx_basic_msr_low;
+        vmx_caps.basic_msr = ((uint64_t)vmx_basic_msr_high << 32) |
+                             vmx_basic_msr_low;
         vmx_vmfunc                 = _vmx_vmfunc;
 
         vmx_display_features();
@@ -565,7 +565,7 @@ static int vmx_init_vmcs_config(bool bsp)
             mismatch = 1;
         }
         if ( (vmx_basic_msr_high & (VMX_BASIC_VMCS_SIZE_MASK >> 32)) !=
-             ((vmx_basic_msr & VMX_BASIC_VMCS_SIZE_MASK) >> 32) )
+             ((vmx_caps.basic_msr & VMX_BASIC_VMCS_SIZE_MASK) >> 32) )
         {
             printk("VMX: CPU%d unexpected VMCS size %Lu\n",
                    smp_processor_id(),
@@ -2230,7 +2230,7 @@ int __init vmx_vmcs_init(void)
          * _vmx_vcpu_up() may have made it past feature identification.
          * Make sure all dependent features are off as well.
          */
-        vmx_basic_msr              = 0;
+        memset(&vmx_caps, 0, sizeof(vmx_caps));
         vmx_pin_based_exec_control = 0;
         vmx_cpu_based_exec_control = 0;
         vmx_secondary_exec_control = 0;
diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index a3d7d1e4d7..87ac43c5c4 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1561,7 +1561,7 @@ static int nvmx_handle_vmxon(struct cpu_user_regs *regs)
     rc = hvm_copy_from_guest_phys(&nvmcs_revid, gpa, sizeof(nvmcs_revid));
     if ( rc != HVMTRANS_okay ||
          (nvmcs_revid & ~VMX_BASIC_REVISION_MASK) ||
-         ((nvmcs_revid ^ vmx_basic_msr) & VMX_BASIC_REVISION_MASK) )
+         ((nvmcs_revid ^ vmx_caps.basic_msr) & VMX_BASIC_REVISION_MASK) )
     {
         vmfail_invalid(regs);
         return X86EMUL_OKAY;
@@ -1799,7 +1799,7 @@ static int nvmx_handle_vmptrld(struct cpu_user_regs *regs)
             {
                 struct vmcs_struct *vvmcs = vvmcx;
 
-                if ( ((vvmcs->revision_id ^ vmx_basic_msr) &
+                if ( ((vvmcs->revision_id ^ vmx_caps.basic_msr) &
                       VMX_BASIC_REVISION_MASK) ||
                      (!cpu_has_vmx_vmcs_shadowing &&
                       (vvmcs->revision_id & ~VMX_BASIC_REVISION_MASK)) )
@@ -2193,7 +2193,7 @@ int nvmx_msr_read_intercept(unsigned int msr, u64 
*msr_content)
     case MSR_IA32_VMX_TRUE_PROCBASED_CTLS:
     case MSR_IA32_VMX_TRUE_EXIT_CTLS:
     case MSR_IA32_VMX_TRUE_ENTRY_CTLS:
-        if ( !(vmx_basic_msr & VMX_BASIC_DEFAULT1_ZERO) )
+        if ( !(vmx_caps.basic_msr & VMX_BASIC_DEFAULT1_ZERO) )
             return 0;
         break;
 
diff --git a/xen/arch/x86/include/asm/hvm/vmx/vmcs.h 
b/xen/arch/x86/include/asm/hvm/vmx/vmcs.h
index d9d64764ef..5efa3e9659 100644
--- a/xen/arch/x86/include/asm/hvm/vmx/vmcs.h
+++ b/xen/arch/x86/include/asm/hvm/vmx/vmcs.h
@@ -300,6 +300,12 @@ extern u64 vmx_ept_vpid_cap;
 
 #define VMX_TSC_MULTIPLIER_MAX                  0xffffffffffffffffULL
 
+/* Capabilities and dynamic (run-time adjusted) execution control flags. */
+struct vmx_caps {
+    uint64_t basic_msr;
+};
+extern struct vmx_caps vmx_caps;
+
 #define cpu_has_wbinvd_exiting \
     (IS_ENABLED(CONFIG_INTEL_VMX) && \
      vmx_secondary_exec_control & SECONDARY_EXEC_WBINVD_EXITING)
@@ -415,9 +421,8 @@ extern u64 vmx_ept_vpid_cap;
  */
 #define VMX_BASIC_DEFAULT1_ZERO                (1ULL << 55)
 
-extern u64 vmx_basic_msr;
 #define cpu_has_vmx_ins_outs_instr_info \
-    (!!(vmx_basic_msr & VMX_BASIC_INS_OUT_INFO))
+    (!!(vmx_caps.basic_msr & VMX_BASIC_INS_OUT_INFO))
 
 /* Guest interrupt status */
 #define VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK  0x0FF
--
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