Commit 74cdc836 authored by Mathias Krause's avatar Mathias Krause Committed by Sean Christopherson
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KVM: x86: Make use of kvm_read_cr*_bits() when testing bits 



Make use of the kvm_read_cr{0,4}_bits() helper functions when we only
want to know the state of certain bits instead of the whole register.

This not only makes the intent cleaner, it also avoids a potential
VMREAD in case the tested bits aren't guest owned.

Signed-off-by: default avatarMathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20230322013731.102955-5-minipli@grsecurity.net


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent e40bcf9f

arch/x86/kvm/pmu.c

+2 −2
Original line number Diff line number Diff line
@@ -540,9 +540,9 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) 
	if (!pmc)

		return 1;



	if (!(kvm_read_cr4(vcpu) & X86_CR4_PCE) &&

	if (!(kvm_read_cr4_bits(vcpu, X86_CR4_PCE)) &&

	    (static_call(kvm_x86_get_cpl)(vcpu) != 0) &&

	    (kvm_read_cr0(vcpu) & X86_CR0_PE))

	    (kvm_read_cr0_bits(vcpu, X86_CR0_PE)))

		return 1;



	*data = pmc_read_counter(pmc) & mask;

arch/x86/kvm/vmx/vmx.c

+2 −2
Original line number Diff line number Diff line
@@ -5517,7 +5517,7 @@ static int handle_cr(struct kvm_vcpu *vcpu) 
		break;

	case 3: /* lmsw */

		val = (exit_qualification >> LMSW_SOURCE_DATA_SHIFT) & 0x0f;

		trace_kvm_cr_write(0, (kvm_read_cr0(vcpu) & ~0xful) | val);

		trace_kvm_cr_write(0, (kvm_read_cr0_bits(vcpu, ~0xful) | val));

		kvm_lmsw(vcpu, val);



		return kvm_skip_emulated_instruction(vcpu);
@@ -7575,7 +7575,7 @@ static u8 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio) 
	if (!kvm_arch_has_noncoherent_dma(vcpu->kvm))

		return (MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT) | VMX_EPT_IPAT_BIT;



	if (kvm_read_cr0(vcpu) & X86_CR0_CD) {

	if (kvm_read_cr0_bits(vcpu, X86_CR0_CD)) {

		if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_CD_NW_CLEARED))

			cache = MTRR_TYPE_WRBACK;

		else