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KVM: VMX: Combine "check" and "get" APIs for passthrough MSR lookups

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Combine possible_passthrough_msr_slot() and is_valid_passthrough_msr()
into a single function, vmx_get_passthrough_msr_slot(), and have the
combined helper return the slot on success, using a negative value to
indicate "failure".

Combining the operations avoids iterating over the array of passthrough
MSRs twice for relevant MSRs.

Suggested-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Dongli Zhang <dongli.zhang@oracle.com>
Link: https://lore.kernel.org/r/20240223202104.3330974-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2024-02-23 12:21:04 -08:00
parent bab22040d7
commit 259720c37d
1 changed files with 26 additions and 39 deletions
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45
arch/x86/kvm/vmx/vmx.c
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@ -658,25 +658,14 @@ static inline bool cpu_need_virtualize_apic_accesses(struct kvm_vcpu *vcpu)
return flexpriority_enabled && lapic_in_kernel(vcpu);
}
static int possible_passthrough_msr_slot(u32 msr)
static int vmx_get_passthrough_msr_slot(u32 msr)
{
u32 i;
for (i = 0; i < ARRAY_SIZE(vmx_possible_passthrough_msrs); i++)
if (vmx_possible_passthrough_msrs[i] == msr)
return i;
return -ENOENT;
}
static bool is_valid_passthrough_msr(u32 msr)
{
bool r;
int i;
switch (msr) {
case 0x800 ... 0x8ff:
/* x2APIC MSRs. These are handled in vmx_update_msr_bitmap_x2apic() */
return true;
return -ENOENT;
case MSR_IA32_RTIT_STATUS:
case MSR_IA32_RTIT_OUTPUT_BASE:
case MSR_IA32_RTIT_OUTPUT_MASK:
@ -691,14 +680,16 @@ static bool is_valid_passthrough_msr(u32 msr)
case MSR_LBR_CORE_FROM ... MSR_LBR_CORE_FROM + 8:
case MSR_LBR_CORE_TO ... MSR_LBR_CORE_TO + 8:
/* LBR MSRs. These are handled in vmx_update_intercept_for_lbr_msrs() */
return true;
return -ENOENT;
}
r = possible_passthrough_msr_slot(msr) != -ENOENT;
for (i = 0; i < ARRAY_SIZE(vmx_possible_passthrough_msrs); i++) {
if (vmx_possible_passthrough_msrs[i] == msr)
return i;
}
WARN(!r, "Invalid MSR %x, please adapt vmx_possible_passthrough_msrs[]", msr);
return r;
WARN(1, "Invalid MSR %x, please adapt vmx_possible_passthrough_msrs[]", msr);
return -ENOENT;
}
struct vmx_uret_msr *vmx_find_uret_msr(struct vcpu_vmx *vmx, u32 msr)
@ -3954,6 +3945,7 @@ void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap;
int idx;
if (!cpu_has_vmx_msr_bitmap())
return;
@ -3964,16 +3956,13 @@ void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
* Mark the desired intercept state in shadow bitmap, this is needed
* for resync when the MSR filters change.
*/
if (is_valid_passthrough_msr(msr)) {
int idx = possible_passthrough_msr_slot(msr);
if (idx != -ENOENT) {
idx = vmx_get_passthrough_msr_slot(msr);
if (idx >= 0) {
if (type & MSR_TYPE_R)
clear_bit(idx, vmx->shadow_msr_intercept.read);
if (type & MSR_TYPE_W)
clear_bit(idx, vmx->shadow_msr_intercept.write);
}
}
if ((type & MSR_TYPE_R) &&
!kvm_msr_allowed(vcpu, msr, KVM_MSR_FILTER_READ)) {
@ -3998,6 +3987,7 @@ void vmx_enable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap;
int idx;
if (!cpu_has_vmx_msr_bitmap())
return;
@ -4008,16 +3998,13 @@ void vmx_enable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type)
* Mark the desired intercept state in shadow bitmap, this is needed
* for resync when the MSR filter changes.
*/
if (is_valid_passthrough_msr(msr)) {
int idx = possible_passthrough_msr_slot(msr);
if (idx != -ENOENT) {
idx = vmx_get_passthrough_msr_slot(msr);
if (idx >= 0) {
if (type & MSR_TYPE_R)
set_bit(idx, vmx->shadow_msr_intercept.read);
if (type & MSR_TYPE_W)
set_bit(idx, vmx->shadow_msr_intercept.write);
}
}
if (type & MSR_TYPE_R)
vmx_set_msr_bitmap_read(msr_bitmap, msr);