KVM: nVMX: Add a helper to encode VMCS info in MSR_IA32_VMX_BASIC

Add a helper to encode the VMCS revision, size, and supported memory types
in MSR_IA32_VMX_BASIC, i.e. when synthesizing KVM's supported BASIC MSR
value, and delete the now unused VMCS size and memtype shift macros.

For a variety of reasons, KVM has shifted (pun intended) to using helpers
to *get* information from the VMX MSRs, as opposed to defined MASK and
SHIFT macros for direct use.  Provide a similar helper for the nested VMX
code, which needs to *set* information, so that KVM isn't left with a mix
of SHIFT macros and dedicated helpers.

Reported-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20240605231918.2915961-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 90963b14afaad7c6ab2f22d97f90ea75b566d13f..65aaf0577265421f71bfae12c4479e45ac45686c 100644 (file)
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -135,10 +135,8 @@
 #define VMX_VMFUNC_EPTP_SWITCHING               VMFUNC_CONTROL_BIT(EPTP_SWITCHING)
 #define VMFUNC_EPTP_ENTRIES  512
 
-#define VMX_BASIC_VMCS_SIZE_SHIFT              32
 #define VMX_BASIC_32BIT_PHYS_ADDR_ONLY         BIT_ULL(48)
 #define VMX_BASIC_DUAL_MONITOR_TREATMENT       BIT_ULL(49)
-#define VMX_BASIC_MEM_TYPE_SHIFT               50
 #define VMX_BASIC_INOUT                                BIT_ULL(54)
 #define VMX_BASIC_TRUE_CTLS                    BIT_ULL(55)
 
@@ -157,6 +155,11 @@ static inline u32 vmx_basic_vmcs_mem_type(u64 vmx_basic)
        return (vmx_basic & GENMASK_ULL(53, 50)) >> 50;
 }
 
+static inline u64 vmx_basic_encode_vmcs_info(u32 revision, u16 size, u8 memtype)
+{
+       return revision | ((u64)size << 32) | ((u64)memtype << 50);
+}
+
 static inline int vmx_misc_preemption_timer_rate(u64 vmx_misc)
 {
        return vmx_misc & VMX_MISC_PREEMPTION_TIMER_RATE_MASK;

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index eba5e94a3c7c0d1151946fa1e06aaf625c5401cb..335f1a650497735c8ef36e8afdf42cd57da252a1 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -7077,12 +7077,10 @@ static void nested_vmx_setup_basic(struct nested_vmx_msrs *msrs)
         * guest, and the VMCS structure we give it - not about the
         * VMX support of the underlying hardware.
         */
-       msrs->basic =
-               VMCS12_REVISION |
-               VMX_BASIC_TRUE_CTLS |
-               ((u64)VMCS12_SIZE << VMX_BASIC_VMCS_SIZE_SHIFT) |
-               (X86_MEMTYPE_WB << VMX_BASIC_MEM_TYPE_SHIFT);
+       msrs->basic = vmx_basic_encode_vmcs_info(VMCS12_REVISION, VMCS12_SIZE,
+                                                X86_MEMTYPE_WB);
 
+       msrs->basic |= VMX_BASIC_TRUE_CTLS;
        if (cpu_has_vmx_basic_inout())
                msrs->basic |= VMX_BASIC_INOUT;
 }