Commit 259720c3 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

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



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: default avatarDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: default avatarDongli Zhang <dongli.zhang@oracle.com>
Link: https://lore.kernel.org/r/20240223202104.3330974-4-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent bab22040

arch/x86/kvm/vmx/vmx.c

+26 −39
Original line number Diff line number Diff line
@@ -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;



	WARN(!r, "Invalid MSR %x, please adapt vmx_possible_passthrough_msrs[]", msr);

	for (i = 0; i < ARRAY_SIZE(vmx_possible_passthrough_msrs); i++) {

		if (vmx_possible_passthrough_msrs[i] == msr)

			return i;

	}



	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);