KVM: MMU: record maximum physical address width in kvm_mmu_extended_role

Previously, commit 7dcd575 ("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 <[email protected]> Cc: [email protected] Signed-off-by: Paolo Bonzini <[email protected]>
openbmc · Feb 22, 2019 · de3ccd2 · de3ccd2
1 parent 511da98
commit de3ccd2
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diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
@@ -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;
 	};
 };
 

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
@@ -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;