| Message ID | 20231229022652.300095-1-chao.gao@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: VMX: Report up-to-date exit qualification to userspace | expand |
On Fri, Dec 29, 2023, Chao Gao wrote: > Use vmx_get_exit_qual() to read the exit qualification. > > vcpu->arch.exit_qualification is cached for EPT violation only and even > for EPT violation, it is stale at this point because the up-to-date > value is cached later in handle_ept_violation(). Oof, vcpu->arch.exit_qualification is *gross*. At a glance, it should be straightforward to get rid of it and use the fault structure to pass the info that comes from the MMU. I'll post a patch, assuming it works. As for this patch, I'll get it applied for 6.9. --- arch/x86/include/asm/kvm_host.h | 3 --- arch/x86/kvm/kvm_emulate.h | 1 + arch/x86/kvm/mmu/paging_tmpl.h | 14 +++++++------- arch/x86/kvm/vmx/nested.c | 5 ++++- arch/x86/kvm/vmx/vmx.c | 2 -- 5 files changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ad5319a503f0..7ef4715d43d6 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -993,9 +993,6 @@ struct kvm_vcpu_arch { u64 msr_kvm_poll_control; - /* set at EPT violation at this point */ - unsigned long exit_qualification; - /* pv related host specific info */ struct { bool pv_unhalted; diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 4351149484fb..b5791a66637e 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -26,6 +26,7 @@ struct x86_exception { bool nested_page_fault; u64 address; /* cr2 or nested page fault gpa */ u8 async_page_fault; + unsigned long exit_qualification; }; /* diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 4d4e98fe4f35..7a87097cb45b 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -497,21 +497,21 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, * The other bits are set to 0. */ if (!(errcode & PFERR_RSVD_MASK)) { - vcpu->arch.exit_qualification &= (EPT_VIOLATION_GVA_IS_VALID | - EPT_VIOLATION_GVA_TRANSLATED); + walker->fault.exit_qualification = 0; + if (write_fault) - vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_WRITE; + walker->fault.exit_qualification |= EPT_VIOLATION_ACC_WRITE; if (user_fault) - vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_READ; + walker->fault.exit_qualification |= EPT_VIOLATION_ACC_READ; if (fetch_fault) - vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_INSTR; + walker->fault.exit_qualification |= EPT_VIOLATION_ACC_INSTR; /* * Note, pte_access holds the raw RWX bits from the EPTE, not * ACC_*_MASK flags! */ - vcpu->arch.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) << - EPT_VIOLATION_RWX_SHIFT; + walker->fault.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) << + EPT_VIOLATION_RWX_SHIFT; } #endif walker->fault.address = addr; diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 994e014f8a50..15141b08c604 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -407,10 +407,13 @@ static void nested_ept_invalidate_addr(struct kvm_vcpu *vcpu, gpa_t eptp, static void nested_ept_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault) { + unsigned long exit_qualification = fault->exit_qualification; struct vmcs12 *vmcs12 = get_vmcs12(vcpu); struct vcpu_vmx *vmx = to_vmx(vcpu); u32 vm_exit_reason; - unsigned long exit_qualification = vcpu->arch.exit_qualification; + + exit_qualification |= vmx_get_exit_qual(vcpu) & + (EPT_VIOLATION_GVA_IS_VALID | EPT_VIOLATION_GVA_TRANSLATED); if (vmx->nested.pml_full) { vm_exit_reason = EXIT_REASON_PML_FULL; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index e262bc2ba4e5..1de022af7dcb 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -5771,8 +5771,6 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu) error_code |= (exit_qualification & EPT_VIOLATION_GVA_TRANSLATED) != 0 ? PFERR_GUEST_FINAL_MASK : PFERR_GUEST_PAGE_MASK; - vcpu->arch.exit_qualification = exit_qualification; - /* * Check that the GPA doesn't exceed physical memory limits, as that is * a guest page fault. We have to emulate the instruction here, because base-commit: 873eef46b33c86be414d60bd00390e64fc0f006f --
On Fri, 29 Dec 2023 10:26:52 +0800, Chao Gao wrote: > Use vmx_get_exit_qual() to read the exit qualification. > > vcpu->arch.exit_qualification is cached for EPT violation only and even > for EPT violation, it is stale at this point because the up-to-date > value is cached later in handle_ept_violation(). > > > [...] Applied to kvm-x86 vmx, thanks! [1/1] KVM: VMX: Report up-to-date exit qualification to userspace https://github.com/kvm-x86/linux/commit/d7f0a00e438d -- https://github.com/kvm-x86/linux/tree/next
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 40e3780d73ae..46d6ee3c52e5 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6510,7 +6510,7 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_DELIVERY_EV; vcpu->run->internal.data[0] = vectoring_info; vcpu->run->internal.data[1] = exit_reason.full; - vcpu->run->internal.data[2] = vcpu->arch.exit_qualification; + vcpu->run->internal.data[2] = vmx_get_exit_qual(vcpu); if (exit_reason.basic == EXIT_REASON_EPT_MISCONFIG) { vcpu->run->internal.data[ndata++] = vmcs_read64(GUEST_PHYSICAL_ADDRESS);
Use vmx_get_exit_qual() to read the exit qualification. vcpu->arch.exit_qualification is cached for EPT violation only and even for EPT violation, it is stale at this point because the up-to-date value is cached later in handle_ept_violation(). Fixes: 70bcd708dfd1 ("KVM: vmx: expose more information for KVM_INTERNAL_ERROR_DELIVERY_EV exits") Signed-off-by: Chao Gao <chao.gao@intel.com> --- arch/x86/kvm/vmx/vmx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) base-commit: 8ed26ab8d59111c2f7b86d200d1eb97d2a458fd1