Commit 89786147 authored by Mohammed Gamal's avatar Mohammed Gamal Committed by Paolo Bonzini
Browse files

KVM: x86: Add helper functions for illegal GPA checking and page fault injection 



This patch adds two helper functions that will be used to support virtualizing
MAXPHYADDR in both kvm-intel.ko and kvm.ko.

kvm_fixup_and_inject_pf_error() injects a page fault for a user-specified GVA,
while kvm_mmu_is_illegal_gpa() checks whether a GPA exceeds vCPU address limits.

Signed-off-by: default avatarMohammed Gamal <mgamal@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200710154811.418214-2-mgamal@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent fe9304d3

arch/x86/kvm/mmu.h

+6 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


#include <linux/kvm_host.h>

#include "kvm_cache_regs.h"

#include "cpuid.h"



#define PT64_PT_BITS 9

#define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
@@ -150,6 +151,11 @@ static inline bool is_write_protection(struct kvm_vcpu *vcpu) 
	return kvm_read_cr0_bits(vcpu, X86_CR0_WP);

}



static inline bool kvm_mmu_is_illegal_gpa(struct kvm_vcpu *vcpu, gpa_t gpa)

{

        return (gpa >= BIT_ULL(cpuid_maxphyaddr(vcpu)));

}



/*

 * Check if a given access (described through the I/D, W/R and U/S bits of a

 * page fault error code pfec) causes a permission fault with the given PTE

arch/x86/kvm/x86.c

+21 −0
Original line number Diff line number Diff line
@@ -10738,6 +10738,27 @@ int kvm_spec_ctrl_test_value(u64 value) 
}

EXPORT_SYMBOL_GPL(kvm_spec_ctrl_test_value);



void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_code)

{

	struct x86_exception fault;



	if (!(error_code & PFERR_PRESENT_MASK) ||

	    vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, error_code, &fault) != UNMAPPED_GVA) {

		/*

		 * If vcpu->arch.walk_mmu->gva_to_gpa succeeded, the page

		 * tables probably do not match the TLB.  Just proceed

		 * with the error code that the processor gave.

		 */

		fault.vector = PF_VECTOR;

		fault.error_code_valid = true;

		fault.error_code = error_code;

		fault.nested_page_fault = false;

		fault.address = gva;

	}

	vcpu->arch.walk_mmu->inject_page_fault(vcpu, &fault);

}

EXPORT_SYMBOL_GPL(kvm_fixup_and_inject_pf_error);



EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);

EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_fast_mmio);

EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);

arch/x86/kvm/x86.h

+1 −0
Original line number Diff line number Diff line
@@ -272,6 +272,7 @@ int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata); 
bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn,

					  int page_num);

bool kvm_vector_hashing_enabled(void);

void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_code);

int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,

			    int emulation_type, void *insn, int insn_len);

fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu);

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