[PATCH v2 9/9] KVM: x86: Rename GPR accessors to make mode-aware variants the defaults

Sean Christopherson
2021-04-22T02:22:01Z

Append raw to the direct variants of kvm_register_read/write(), and
drop the "l" from the mode-aware variants. I.e. make the mode-aware
variants the default, and make the direct variants scary sounding so as
to discourage use. Accessing the full 64-bit values irrespective of
mode is rarely the desired behavior.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/kvm_cache_regs.h | 19 ++++++++++++-------
arch/x86/kvm/svm/svm.c | 8 ++++----
arch/x86/kvm/vmx/nested.c | 20 ++++++++++----------
arch/x86/kvm/vmx/vmx.c | 12 ++++++------
arch/x86/kvm/x86.c | 8 ++++----
arch/x86/kvm/x86.h | 8 ++++----
arch/x86/kvm/xen.c | 2 +-
7 files changed, 41 insertions(+), 36 deletions(-)

diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index 2e11da2f5621..3db5c42c9ecd 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -62,7 +62,12 @@ static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu,
__set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
}

-static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu, int reg)
+/*
+ * The "raw" register helpers are only for cases where the full 64 bits of a
+ * register are read/written irrespective of current vCPU mode. In other words,
+ * odds are good you shouldn't be using the raw variants.
+ */
+static inline unsigned long kvm_register_read_raw(struct kvm_vcpu *vcpu, int reg)
{
if (WARN_ON_ONCE((unsigned int)reg >= NR_VCPU_REGS))
return 0;
@@ -73,8 +78,8 @@ static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu, int reg)
return vcpu->arch.regs[reg];
}

-static inline void kvm_register_write(struct kvm_vcpu *vcpu, int reg,
- unsigned long val)
+static inline void kvm_register_write_raw(struct kvm_vcpu *vcpu, int reg,
+ unsigned long val)
{
if (WARN_ON_ONCE((unsigned int)reg >= NR_VCPU_REGS))
return;
@@ -85,22 +90,22 @@ static inline void kvm_register_write(struct kvm_vcpu *vcpu, int reg,

static inline unsigned long kvm_rip_read(struct kvm_vcpu *vcpu)
{
- return kvm_register_read(vcpu, VCPU_REGS_RIP);
+ return kvm_register_read_raw(vcpu, VCPU_REGS_RIP);
}

static inline void kvm_rip_write(struct kvm_vcpu *vcpu, unsigned long val)
{
- kvm_register_write(vcpu, VCPU_REGS_RIP, val);
+ kvm_register_write_raw(vcpu, VCPU_REGS_RIP, val);
}

static inline unsigned long kvm_rsp_read(struct kvm_vcpu *vcpu)
{
- return kvm_register_read(vcpu, VCPU_REGS_RSP);
+ return kvm_register_read_raw(vcpu, VCPU_REGS_RSP);
}

static inline void kvm_rsp_write(struct kvm_vcpu *vcpu, unsigned long val)
{
- kvm_register_write(vcpu, VCPU_REGS_RSP, val);
+ kvm_register_write_raw(vcpu, VCPU_REGS_RSP, val);
}

static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ccf9499f2683..96df12157a8a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2468,7 +2468,7 @@ static int cr_interception(struct kvm_vcpu *vcpu)
err = 0;
if (cr >= 16) { /* mov to cr */
cr -= 16;
- val = kvm_register_readl(vcpu, reg);
+ val = kvm_register_read(vcpu, reg);
trace_kvm_cr_write(cr, val);
switch (cr) {
case 0:
@@ -2514,7 +2514,7 @@ static int cr_interception(struct kvm_vcpu *vcpu)
kvm_queue_exception(vcpu, UD_VECTOR);
return 1;
}
- kvm_register_writel(vcpu, reg, val);
+ kvm_register_write(vcpu, reg, val);
trace_kvm_cr_read(cr, val);
}
return kvm_complete_insn_gp(vcpu, err);
@@ -2580,11 +2580,11 @@ static int dr_interception(struct kvm_vcpu *vcpu)
dr = svm->vmcb->control.exit_code - SVM_EXIT_READ_DR0;
if (dr >= 16) { /* mov to DRn */
dr -= 16;
- val = kvm_register_readl(vcpu, reg);
+ val = kvm_register_read(vcpu, reg);
err = kvm_set_dr(vcpu, dr, val);
} else {
kvm_get_dr(vcpu, dr, &val);
- kvm_register_writel(vcpu, reg, val);
+ kvm_register_write(vcpu, reg, val);
}

return kvm_complete_insn_gp(vcpu, err);
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4daf1ff45221..89976c95091e 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4617,9 +4617,9 @@ int get_vmx_mem_address(struct kvm_vcpu *vcpu, unsigned long exit_qualification,
else if (addr_size == 0)
off = (gva_t)sign_extend64(off, 15);
if (base_is_valid)
- off += kvm_register_readl(vcpu, base_reg);
+ off += kvm_register_read(vcpu, base_reg);
if (index_is_valid)
- off += kvm_register_readl(vcpu, index_reg) << scaling;
+ off += kvm_register_read(vcpu, index_reg) << scaling;
vmx_get_segment(vcpu, &s, seg_reg);

/*
@@ -5021,7 +5021,7 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
return nested_vmx_failInvalid(vcpu);

/* Decode instruction info and find the field to read */
- field = kvm_register_readl(vcpu, (((instr_info) >> 28) & 0xf));
+ field = kvm_register_read(vcpu, (((instr_info) >> 28) & 0xf));

offset = vmcs_field_to_offset(field);
if (offset < 0)
@@ -5039,7 +5039,7 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
* on the guest's mode (32 or 64 bit), not on the given field's length.
*/
if (instr_info & BIT(10)) {
- kvm_register_writel(vcpu, (((instr_info) >> 3) & 0xf), value);
+ kvm_register_write(vcpu, (((instr_info) >> 3) & 0xf), value);
} else {
len = is_64_bit_mode(vcpu) ? 8 : 4;
if (get_vmx_mem_address(vcpu, exit_qualification,
@@ -5113,7 +5113,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
return nested_vmx_failInvalid(vcpu);

if (instr_info & BIT(10))
- value = kvm_register_readl(vcpu, (((instr_info) >> 3) & 0xf));
+ value = kvm_register_read(vcpu, (((instr_info) >> 3) & 0xf));
else {
len = is_64_bit_mode(vcpu) ? 8 : 4;
if (get_vmx_mem_address(vcpu, exit_qualification,
@@ -5124,7 +5124,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
return kvm_handle_memory_failure(vcpu, r, &e);
}

- field = kvm_register_readl(vcpu, (((instr_info) >> 28) & 0xf));
+ field = kvm_register_read(vcpu, (((instr_info) >> 28) & 0xf));

offset = vmcs_field_to_offset(field);
if (offset < 0)
@@ -5321,7 +5321,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)
return 1;

vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
- type = kvm_register_readl(vcpu, (vmx_instruction_info >> 28) & 0xf);
+ type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf);

types = (vmx->nested.msrs.ept_caps >> VMX_EPT_EXTENT_SHIFT) & 6;

@@ -5401,7 +5401,7 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
return 1;

vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
- type = kvm_register_readl(vcpu, (vmx_instruction_info >> 28) & 0xf);
+ type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf);

types = (vmx->nested.msrs.vpid_caps &
VMX_VPID_EXTENT_SUPPORTED_MASK) >> 8;
@@ -5657,7 +5657,7 @@ static bool nested_vmx_exit_handled_cr(struct kvm_vcpu *vcpu,
switch ((exit_qualification >> 4) & 3) {
case 0: /* mov to cr */
reg = (exit_qualification >> 8) & 15;
- val = kvm_register_readl(vcpu, reg);
+ val = kvm_register_read(vcpu, reg);
switch (cr) {
case 0:
if (vmcs12->cr0_guest_host_mask &
@@ -5743,7 +5743,7 @@ static bool nested_vmx_exit_handled_vmcs_access(struct kvm_vcpu *vcpu,

/* Decode instruction info and find the field to access */
vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
- field = kvm_register_readl(vcpu, (((vmx_instruction_info) >> 28) & 0xf));
+ field = kvm_register_read(vcpu, (((vmx_instruction_info) >> 28) & 0xf));

/* Out-of-range fields always cause a VM exit from L2 to L1 */
if (field >> 15)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 7ef4c11d655b..13ac981fae1d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5090,7 +5090,7 @@ static int handle_cr(struct kvm_vcpu *vcpu)
reg = (exit_qualification >> 8) & 15;
switch ((exit_qualification >> 4) & 3) {
case 0: /* mov to cr */
- val = kvm_register_readl(vcpu, reg);
+ val = kvm_register_read(vcpu, reg);
trace_kvm_cr_write(cr, val);
switch (cr) {
case 0:
@@ -5132,12 +5132,12 @@ static int handle_cr(struct kvm_vcpu *vcpu)
case 3:
WARN_ON_ONCE(enable_unrestricted_guest);
val = kvm_read_cr3(vcpu);
- kvm_register_writel(vcpu, reg, val);
+ kvm_register_write(vcpu, reg, val);
trace_kvm_cr_read(cr, val);
return kvm_skip_emulated_instruction(vcpu);
case 8:
val = kvm_get_cr8(vcpu);
- kvm_register_writel(vcpu, reg, val);
+ kvm_register_write(vcpu, reg, val);
trace_kvm_cr_read(cr, val);
return kvm_skip_emulated_instruction(vcpu);
}
@@ -5210,10 +5210,10 @@ static int handle_dr(struct kvm_vcpu *vcpu)
unsigned long val;

kvm_get_dr(vcpu, dr, &val);
- kvm_register_writel(vcpu, reg, val);
+ kvm_register_write(vcpu, reg, val);
err = 0;
} else {
- err = kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg));
+ err = kvm_set_dr(vcpu, dr, kvm_register_read(vcpu, reg));
}

out:
@@ -5565,7 +5565,7 @@ static int handle_invpcid(struct kvm_vcpu *vcpu)
}

vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
- type = kvm_register_readl(vcpu, (vmx_instruction_info >> 28) & 0xf);
+ type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf);

if (type > 3) {
kvm_inject_gp(vcpu, 0);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 63af93211871..5e7d1cd2e2a5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6974,12 +6974,12 @@ static bool emulator_guest_has_fxsr(struct x86_emulate_ctxt *ctxt)

static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg)
{
- return kvm_register_read(emul_to_vcpu(ctxt), reg);
+ return kvm_register_read_raw(emul_to_vcpu(ctxt), reg);
}

static void emulator_write_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val)
{
- kvm_register_write(emul_to_vcpu(ctxt), reg, val);
+ kvm_register_write_raw(emul_to_vcpu(ctxt), reg, val);
}

static void emulator_set_nmi_mask(struct x86_emulate_ctxt *ctxt, bool masked)
@@ -8660,7 +8660,7 @@ static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, char *buf)
put_smstate(u32, buf, 0x7ff0, kvm_rip_read(vcpu));

for (i = 0; i < 8; i++)
- put_smstate(u32, buf, 0x7fd0 + i * 4, kvm_register_read(vcpu, i));
+ put_smstate(u32, buf, 0x7fd0 + i * 4, kvm_register_read_raw(vcpu, i));

kvm_get_dr(vcpu, 6, &val);
put_smstate(u32, buf, 0x7fcc, (u32)val);
@@ -8706,7 +8706,7 @@ static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, char *buf)
int i;

for (i = 0; i < 16; i++)
- put_smstate(u64, buf, 0x7ff8 - i * 8, kvm_register_read(vcpu, i));
+ put_smstate(u64, buf, 0x7ff8 - i * 8, kvm_register_read_raw(vcpu, i));

put_smstate(u64, buf, 0x7f78, kvm_rip_read(vcpu));
put_smstate(u32, buf, 0x7f70, kvm_get_rflags(vcpu));
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index daccf20fbcd5..f2a4094532cf 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -232,19 +232,19 @@ static inline bool vcpu_match_mmio_gpa(struct kvm_vcpu *vcpu, gpa_t gpa)
return false;
}

-static inline unsigned long kvm_register_readl(struct kvm_vcpu *vcpu, int reg)
+static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu, int reg)
{
- unsigned long val = kvm_register_read(vcpu, reg);
+ unsigned long val = kvm_register_read_raw(vcpu, reg);

return is_64_bit_mode(vcpu) ? val : (u32)val;
}

-static inline void kvm_register_writel(struct kvm_vcpu *vcpu,
+static inline void kvm_register_write(struct kvm_vcpu *vcpu,
int reg, unsigned long val)
{
if (!is_64_bit_mode(vcpu))
val = (u32)val;
- return kvm_register_write(vcpu, reg, val);
+ return kvm_register_write_raw(vcpu, reg, val);
}

static inline bool kvm_check_has_quirk(struct kvm *kvm, u64 quirk)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 7f27bb65a572..ae17250e1efe 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -673,7 +673,7 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
bool longmode;
u64 input, params[6];

- input = (u64)kvm_register_readl(vcpu, VCPU_REGS_RAX);
+ input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);

/* Hyper-V hypercalls get bit 31 set in EAX */
if ((input & 0x80000000) &&