Commit de3ccd26 authored Feb 01, 2019 by Yu Zhang Committed by Paolo Bonzini Feb 22, 2019

KVM: MMU: record maximum physical address width in kvm_mmu_extended_role



Previously, commit 7dcd5755 ("x86/kvm/mmu: check if tdp/shadow
MMU reconfiguration is needed") offered some optimization to avoid
the unnecessary reconfiguration. Yet one scenario is broken - when
cpuid changes VM's maximum physical address width, reconfiguration
is needed to reset the reserved bits.  Also, the TDP may need to
reset its shadow_root_level when this value is changed.

To fix this, a new field, maxphyaddr, is introduced in the extended
role structure to keep track of the configured guest physical address
width.

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 511da98d

arch/x86/include/asm/kvm_host.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -299,6 +299,7 @@ union kvm_mmu_extended_role {
		unsigned int cr4_smap:1;
		unsigned int cr4_smep:1;
		unsigned int cr4_la57:1;
		unsigned int maxphyaddr:6;
		};
		};

arch/x86/kvm/mmu.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -4777,6 +4777,7 @@ static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu)
		ext.cr4_pse = !!is_pse(vcpu);
		ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE);
		ext.cr4_la57 = !!kvm_read_cr4_bits(vcpu, X86_CR4_LA57);
		ext.maxphyaddr = cpuid_maxphyaddr(vcpu);

		ext.valid = 1;

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