[RFC PATCH v2 10/34] x86/msr: Convert __rdmsr() uses to native_rdmsrq() uses

Xin Li (Intel)
2025-04-22T08:23:59Z

__rdmsr() is the lowest level primitive MSR read API, and its direct
use is NOT preferred. Use its wrapper function native_rdmsrq() instead.

No functional change intended.

This change also prepares for using the alternatives mechanism to access
MSRs: uses of native_rdmsr{,q}() don't need to change, but the approaches
how they perform MSR operations are binary patched during boot time upon
availability of MSR instructions.

Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---
arch/x86/boot/startup/sme.c | 4 ++--
arch/x86/events/amd/brs.c | 2 +-
arch/x86/hyperv/hv_vtl.c | 4 ++--
arch/x86/hyperv/ivm.c | 2 +-
arch/x86/include/asm/mshyperv.h | 2 +-
arch/x86/include/asm/sev-internal.h | 2 +-
arch/x86/kernel/cpu/common.c | 2 +-
arch/x86/kernel/cpu/mce/core.c | 4 ++--
arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 4 ++--
10 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/x86/boot/startup/sme.c b/arch/x86/boot/startup/sme.c
index 591d6a4d2e59..5e147bf5a0a8 100644
--- a/arch/x86/boot/startup/sme.c
+++ b/arch/x86/boot/startup/sme.c
@@ -524,7 +524,7 @@ void __head sme_enable(struct boot_params *bp)
me_mask = 1UL << (ebx & 0x3f);

/* Check the SEV MSR whether SEV or SME is enabled */
- sev_status = msr = __rdmsr(MSR_AMD64_SEV);
+ sev_status = msr = native_rdmsrq(MSR_AMD64_SEV);
feature_mask = (msr & MSR_AMD64_SEV_ENABLED) ? AMD_SEV_BIT : AMD_SME_BIT;

/*
@@ -555,7 +555,7 @@ void __head sme_enable(struct boot_params *bp)
return;

/* For SME, check the SYSCFG MSR */
- msr = __rdmsr(MSR_AMD64_SYSCFG);
+ msr = native_rdmsrq(MSR_AMD64_SYSCFG);
if (!(msr & MSR_AMD64_SYSCFG_MEM_ENCRYPT))
return;
}
diff --git a/arch/x86/events/amd/brs.c b/arch/x86/events/amd/brs.c
index 3f5ecfd80d1e..06f35a6b58a5 100644
--- a/arch/x86/events/amd/brs.c
+++ b/arch/x86/events/amd/brs.c
@@ -49,7 +49,7 @@ static __always_inline void set_debug_extn_cfg(u64 val)

static __always_inline u64 get_debug_extn_cfg(void)
{
- return __rdmsr(MSR_AMD_DBG_EXTN_CFG);
+ return native_rdmsrq(MSR_AMD_DBG_EXTN_CFG);
}

static bool __init amd_brs_detect(void)
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
index 13242ed8ff16..c6343e699154 100644
--- a/arch/x86/hyperv/hv_vtl.c
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -149,11 +149,11 @@ static int hv_vtl_bringup_vcpu(u32 target_vp_index, int cpu, u64 eip_ignored)
input->vp_context.rip = rip;
input->vp_context.rsp = rsp;
input->vp_context.rflags = 0x0000000000000002;
- input->vp_context.efer = __rdmsr(MSR_EFER);
+ input->vp_context.efer = native_rdmsrq(MSR_EFER);
input->vp_context.cr0 = native_read_cr0();
input->vp_context.cr3 = __native_read_cr3();
input->vp_context.cr4 = native_read_cr4();
- input->vp_context.msr_cr_pat = __rdmsr(MSR_IA32_CR_PAT);
+ input->vp_context.msr_cr_pat = native_rdmsrq(MSR_IA32_CR_PAT);
input->vp_context.idtr.limit = idt_ptr.size;
input->vp_context.idtr.base = idt_ptr.address;
input->vp_context.gdtr.limit = gdt_ptr.size;
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 8209de792388..09a165a3c41e 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -111,7 +111,7 @@ u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)

static inline u64 rd_ghcb_msr(void)
{
- return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
+ return native_rdmsrq(MSR_AMD64_SEV_ES_GHCB);
}

static inline void wr_ghcb_msr(u64 val)
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 15d00dace70f..778444310cfb 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -305,7 +305,7 @@ void hv_set_non_nested_msr(unsigned int reg, u64 value);

static __always_inline u64 hv_raw_get_msr(unsigned int reg)
{
- return __rdmsr(reg);
+ return native_rdmsrq(reg);
}

#else /* CONFIG_HYPERV */
diff --git a/arch/x86/include/asm/sev-internal.h b/arch/x86/include/asm/sev-internal.h
index 9da509e52e11..d259bcec220a 100644
--- a/arch/x86/include/asm/sev-internal.h
+++ b/arch/x86/include/asm/sev-internal.h
@@ -96,7 +96,7 @@ int svsm_perform_call_protocol(struct svsm_call *call);

static inline u64 sev_es_rd_ghcb_msr(void)
{
- return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
+ return native_rdmsrq(MSR_AMD64_SEV_ES_GHCB);
}

static __always_inline void sev_es_wr_ghcb_msr(u64 val)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index de1a25217053..10da3da5b81f 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -164,7 +164,7 @@ static void ppin_init(struct cpuinfo_x86 *c)

/* Is the enable bit set? */
if (val & 2UL) {
- c->ppin = __rdmsr(info->msr_ppin);
+ c->ppin = native_rdmsrq(info->msr_ppin);
set_cpu_cap(c, info->feature);
return;
}
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 1ae75ec7ac95..32286bad75e6 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -121,7 +121,7 @@ void mce_prep_record_common(struct mce *m)
{
m->cpuid = cpuid_eax(1);
m->cpuvendor = boot_cpu_data.x86_vendor;
- m->mcgcap = __rdmsr(MSR_IA32_MCG_CAP);
+ m->mcgcap = native_rdmsrq(MSR_IA32_MCG_CAP);
/* need the internal __ version to avoid deadlocks */
m->time = __ktime_get_real_seconds();
}
@@ -1298,7 +1298,7 @@ static noinstr bool mce_check_crashing_cpu(void)
(crashing_cpu != -1 && crashing_cpu != cpu)) {
u64 mcgstatus;

- mcgstatus = __rdmsr(MSR_IA32_MCG_STATUS);
+ mcgstatus = native_rdmsrq(MSR_IA32_MCG_STATUS);

if (boot_cpu_data.x86_vendor == X86_VENDOR_ZHAOXIN) {
if (mcgstatus & MCG_STATUS_LMCES)
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index 9ab033d6856a..185317c6b509 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -482,7 +482,7 @@ int resctrl_arch_pseudo_lock_fn(void *_plr)
* the buffer and evict pseudo-locked memory read earlier from the
* cache.
*/
- saved_msr = __rdmsr(MSR_MISC_FEATURE_CONTROL);
+ saved_msr = native_rdmsrq(MSR_MISC_FEATURE_CONTROL);
native_wrmsrq(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits);
closid_p = this_cpu_read(pqr_state.cur_closid);
rmid_p = this_cpu_read(pqr_state.cur_rmid);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1547bfacd40f..e73c1d5ba6c4 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -380,7 +380,7 @@ static __always_inline void vmx_disable_fb_clear(struct vcpu_vmx *vmx)
if (!vmx->disable_fb_clear)
return;

- msr = __rdmsr(MSR_IA32_MCU_OPT_CTRL);
+ msr = native_rdmsrq(MSR_IA32_MCU_OPT_CTRL);
msr |= FB_CLEAR_DIS;
native_wrmsrq(MSR_IA32_MCU_OPT_CTRL, msr);
/* Cache the MSR value to avoid reading it later */
@@ -7307,7 +7307,7 @@ void noinstr vmx_spec_ctrl_restore_host(struct vcpu_vmx *vmx,
return;

if (flags & VMX_RUN_SAVE_SPEC_CTRL)
- vmx->spec_ctrl = __rdmsr(MSR_IA32_SPEC_CTRL);
+ vmx->spec_ctrl = native_rdmsrq(MSR_IA32_SPEC_CTRL);

/*
* If the guest/host SPEC_CTRL values differ, restore the host value.
--
2.49.0