[PATCH v8 07/10] KVM: nVMX: Add a helper to encode VMCS info in MSR_IA32_VMX_BASIC

Sean Christopherson
2024-06-05T23:19:35Z

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>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/vmx.h | 7 +++++--
arch/x86/kvm/vmx/nested.c | 8 +++-----
2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 90963b14afaa..65aaf0577265 100644
--- 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 6402def985af..bb346ca5b5a0 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -7040,12 +7040,10 @@ 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;
}
--
2.45.1.467.gbab1589fc0-goog