hyperv-tlfs: Change prefix of generic HV_REGISTER_* MSRs to HV_MSR_*

The HV_REGISTER_ are used as arguments to hv_set/get_register(), which
delegate to arch-specific mechanisms for getting/setting synthetic
Hyper-V MSRs.

On arm64, HV_REGISTER_ defines are synthetic VP registers accessed via
the get/set vp registers hypercalls. The naming matches the TLFS
document, although these register names are not specific to arm64.

However, on x86 the prefix HV_REGISTER_ indicates Hyper-V MSRs accessed
via rdmsrl()/wrmsrl(). This is not consistent with the TLFS doc, where
HV_REGISTER_ is *only* used for used for VP register names used by
the get/set register hypercalls.

To fix this inconsistency and prevent future confusion, change the
arch-generic aliases used by callers of hv_set/get_register() to have
the prefix HV_MSR_ instead of HV_REGISTER_.

Use the prefix HV_X64_MSR_ for the x86-only Hyper-V MSRs. On x86, the
generic HV_MSR_'s point to the corresponding HV_X64_MSR_.

Move the arm64 HV_REGISTER_* defines to the asm-generic hyperv-tlfs.h,
since these are not specific to arm64. On arm64, the generic HV_MSR_'s
point to the corresponding HV_REGISTER_.

While at it, rename hv_get/set_registers() and related functions to
hv_get/set_msr(), hv_get/set_nested_msr(), etc. These are only used for
Hyper-V MSRs and this naming makes that clear.

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1708440933-27125-1-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1708440933-27125-1-git-send-email-nunodasneves@linux.microsoft.com>

2 files changed, 21 insertions, 28 deletions

diff --git a/arch/arm64/include/asm/hyperv-tlfs.h b/arch/arm64/include/asm/hyperv-tlfs.h
index bc6c7ac934a1..54846d1d29c3 100644
--- a/arch/arm64/include/asm/hyperv-tlfs.h
+++ b/arch/arm64/include/asm/hyperv-tlfs.h
@@ -22,14 +22,6 @@
  */
 
 /*
- * These Hyper-V registers provide information equivalent to the CPUID
- * instruction on x86/x64.
- */
-#define HV_REGISTER_HYPERVISOR_VERSION		0x00000100 /*CPUID 0x40000002 */
-#define HV_REGISTER_FEATURES			0x00000200 /*CPUID 0x40000003 */
-#define HV_REGISTER_ENLIGHTENMENTS		0x00000201 /*CPUID 0x40000004 */
-
-/*
  * Group C Features. See the asm-generic version of hyperv-tlfs.h
  * for a description of Feature Groups.
  */
@@ -41,28 +33,29 @@
 #define HV_STIMER_DIRECT_MODE_AVAILABLE		BIT(13)
 
 /*
- * Synthetic register definitions equivalent to MSRs on x86/x64
+ * To support arch-generic code calling hv_set/get_register:
+ * - On x86, HV_MSR_ indicates an MSR accessed via rdmsrl/wrmsrl
+ * - On ARM, HV_MSR_ indicates a VP register accessed via hypercall
  */
-#define HV_REGISTER_CRASH_P0		0x00000210
-#define HV_REGISTER_CRASH_P1		0x00000211
-#define HV_REGISTER_CRASH_P2		0x00000212
-#define HV_REGISTER_CRASH_P3		0x00000213
-#define HV_REGISTER_CRASH_P4		0x00000214
-#define HV_REGISTER_CRASH_CTL		0x00000215
+#define HV_MSR_CRASH_P0		(HV_REGISTER_CRASH_P0)
+#define HV_MSR_CRASH_P1		(HV_REGISTER_CRASH_P1)
+#define HV_MSR_CRASH_P2		(HV_REGISTER_CRASH_P2)
+#define HV_MSR_CRASH_P3		(HV_REGISTER_CRASH_P3)
+#define HV_MSR_CRASH_P4		(HV_REGISTER_CRASH_P4)
+#define HV_MSR_CRASH_CTL	(HV_REGISTER_CRASH_CTL)
 
-#define HV_REGISTER_GUEST_OSID		0x00090002
-#define HV_REGISTER_VP_INDEX		0x00090003
-#define HV_REGISTER_TIME_REF_COUNT	0x00090004
-#define HV_REGISTER_REFERENCE_TSC	0x00090017
+#define HV_MSR_VP_INDEX		(HV_REGISTER_VP_INDEX)
+#define HV_MSR_TIME_REF_COUNT	(HV_REGISTER_TIME_REF_COUNT)
+#define HV_MSR_REFERENCE_TSC	(HV_REGISTER_REFERENCE_TSC)
 
-#define HV_REGISTER_SINT0		0x000A0000
-#define HV_REGISTER_SCONTROL		0x000A0010
-#define HV_REGISTER_SIEFP		0x000A0012
-#define HV_REGISTER_SIMP		0x000A0013
-#define HV_REGISTER_EOM			0x000A0014
+#define HV_MSR_SINT0		(HV_REGISTER_SINT0)
+#define HV_MSR_SCONTROL		(HV_REGISTER_SCONTROL)
+#define HV_MSR_SIEFP		(HV_REGISTER_SIEFP)
+#define HV_MSR_SIMP		(HV_REGISTER_SIMP)
+#define HV_MSR_EOM		(HV_REGISTER_EOM)
 
-#define HV_REGISTER_STIMER0_CONFIG	0x000B0000
-#define HV_REGISTER_STIMER0_COUNT	0x000B0001
+#define HV_MSR_STIMER0_CONFIG	(HV_REGISTER_STIMER0_CONFIG)
+#define HV_MSR_STIMER0_COUNT	(HV_REGISTER_STIMER0_COUNT)
 
 union hv_msi_entry {
 	u64 as_uint64[2];
diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h
index 20070a847304..a975e1a689dd 100644
--- a/arch/arm64/include/asm/mshyperv.h
+++ b/arch/arm64/include/asm/mshyperv.h
@@ -31,12 +31,12 @@ void hv_set_vpreg(u32 reg, u64 value);
 u64 hv_get_vpreg(u32 reg);
 void hv_get_vpreg_128(u32 reg, struct hv_get_vp_registers_output *result);
 
-static inline void hv_set_register(unsigned int reg, u64 value)
+static inline void hv_set_msr(unsigned int reg, u64 value)
 {
 	hv_set_vpreg(reg, value);
 }
 
-static inline u64 hv_get_register(unsigned int reg)
+static inline u64 hv_get_msr(unsigned int reg)
 {
 	return hv_get_vpreg(reg);
 }