KVM: Move KVM_REG_SIZE() definition to common uAPI header

Define KVM_REG_SIZE() in the common kvm.h header, and delete the arm64 and
RISC-V versions.  As evidenced by the surrounding definitions, all aspects
of the register size encoding are generic, i.e. RISC-V should have moved
arm64's definition to common code instead of copy+pasting.

Acked-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20241128005547.4077116-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

arch/arm64/include/uapi/asm/kvm.h

@@ -43,9 +43,6 @@
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 #define KVM_DIRTY_LOG_PAGE_OFFSET 64
 
-#define KVM_REG_SIZE(id)						\
-	(1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
-
 struct kvm_regs {
 	struct user_pt_regs regs;	/* sp = sp_el0 */
 

arch/riscv/include/uapi/asm/kvm.h

@@ -211,9 +211,6 @@ struct kvm_riscv_sbi_sta {
 #define KVM_RISCV_TIMER_STATE_OFF	0
 #define KVM_RISCV_TIMER_STATE_ON	1
 
-#define KVM_REG_SIZE(id)		\
-	(1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
-
 /* If you need to interpret the index values, here is the key: */
 #define KVM_REG_RISCV_TYPE_MASK		0x00000000FF000000
 #define KVM_REG_RISCV_TYPE_SHIFT	24

include/uapi/linux/kvm.h

@@ -1070,6 +1070,10 @@ struct kvm_dirty_tlb {
 
 #define KVM_REG_SIZE_SHIFT	52
 #define KVM_REG_SIZE_MASK	0x00f0000000000000ULL
+
+#define KVM_REG_SIZE(id)		\
+	(1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
+
 #define KVM_REG_SIZE_U8		0x0000000000000000ULL
 #define KVM_REG_SIZE_U16	0x0010000000000000ULL
 #define KVM_REG_SIZE_U32	0x0020000000000000ULL