On Fri, Jun 19, 2020 at 05:39:15PM +0200, Mohammed Gamal wrote:
> 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: Mohammed Gamal <mgamal@xxxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.h | 6 ++++++
> arch/x86/kvm/x86.c | 21 +++++++++++++++++++++
> arch/x86/kvm/x86.h | 1 +
> 3 files changed, 28 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
> index 0ad06bfe2c2c..555237dfb91c 100644
> --- a/arch/x86/kvm/mmu.h
> +++ b/arch/x86/kvm/mmu.h
> @@ -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)
> @@ -158,6 +159,11 @@ 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
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 00c88c2f34e4..ac8642e890b1 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -10693,6 +10693,27 @@ u64 kvm_spec_ctrl_valid_bits(struct kvm_vcpu *vcpu)
> }
> EXPORT_SYMBOL_GPL(kvm_spec_ctrl_valid_bits);
>
> +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);
Should this "vcpu->arch.walk_mmu->inject_page_fault(vcpu, &fault)" inside the last brace?
Otherwise an uninitialized fault variable will be passed to the walk_mmu->inject_page_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);
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index 6eb62e97e59f..239ae0f3e40b 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -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);
> --
> 2.26.2
>
