From: Nadav Har'El Date: Wed, 25 May 2011 20:10:02 +0000 (+0300) Subject: KVM: nVMX: Prepare vmcs02 from vmcs01 and vmcs12 X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=fe3ef05c7572d68721c1ddd4d36009611f565ba2;p=openwrt%2Fstaging%2Fblogic.git KVM: nVMX: Prepare vmcs02 from vmcs01 and vmcs12 This patch contains code to prepare the VMCS which can be used to actually run the L2 guest, vmcs02. prepare_vmcs02 appropriately merges the information in vmcs12 (the vmcs that L1 built for L2) and in vmcs01 (our desires for our own guests). Signed-off-by: Nadav Har'El Signed-off-by: Marcelo Tosatti --- diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 3134638e9e90..506c9144074a 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -345,6 +345,12 @@ struct nested_vmx { /* vmcs02_list cache of VMCSs recently used to run L2 guests */ struct list_head vmcs02_pool; int vmcs02_num; + u64 vmcs01_tsc_offset; + /* + * Guest pages referred to in vmcs02 with host-physical pointers, so + * we must keep them pinned while L2 runs. + */ + struct page *apic_access_page; }; struct vcpu_vmx { @@ -847,6 +853,18 @@ static inline bool report_flexpriority(void) return flexpriority_enabled; } +static inline bool nested_cpu_has(struct vmcs12 *vmcs12, u32 bit) +{ + return vmcs12->cpu_based_vm_exec_control & bit; +} + +static inline bool nested_cpu_has2(struct vmcs12 *vmcs12, u32 bit) +{ + return (vmcs12->cpu_based_vm_exec_control & + CPU_BASED_ACTIVATE_SECONDARY_CONTROLS) && + (vmcs12->secondary_vm_exec_control & bit); +} + static int __find_msr_index(struct vcpu_vmx *vmx, u32 msr) { int i; @@ -1441,6 +1459,22 @@ static void vmx_fpu_activate(struct kvm_vcpu *vcpu) static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu); +/* + * Return the cr0 value that a nested guest would read. This is a combination + * of the real cr0 used to run the guest (guest_cr0), and the bits shadowed by + * its hypervisor (cr0_read_shadow). + */ +static inline unsigned long nested_read_cr0(struct vmcs12 *fields) +{ + return (fields->guest_cr0 & ~fields->cr0_guest_host_mask) | + (fields->cr0_read_shadow & fields->cr0_guest_host_mask); +} +static inline unsigned long nested_read_cr4(struct vmcs12 *fields) +{ + return (fields->guest_cr4 & ~fields->cr4_guest_host_mask) | + (fields->cr4_read_shadow & fields->cr4_guest_host_mask); +} + static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu) { vmx_decache_cr0_guest_bits(vcpu); @@ -3438,6 +3472,9 @@ static void set_cr4_guest_host_mask(struct vcpu_vmx *vmx) vmx->vcpu.arch.cr4_guest_owned_bits = KVM_CR4_GUEST_OWNED_BITS; if (enable_ept) vmx->vcpu.arch.cr4_guest_owned_bits |= X86_CR4_PGE; + if (is_guest_mode(&vmx->vcpu)) + vmx->vcpu.arch.cr4_guest_owned_bits &= + ~get_vmcs12(&vmx->vcpu)->cr4_guest_host_mask; vmcs_writel(CR4_GUEST_HOST_MASK, ~vmx->vcpu.arch.cr4_guest_owned_bits); } @@ -4736,6 +4773,11 @@ static void free_nested(struct vcpu_vmx *vmx) vmx->nested.current_vmptr = -1ull; vmx->nested.current_vmcs12 = NULL; } + /* Unpin physical memory we referred to in current vmcs02 */ + if (vmx->nested.apic_access_page) { + nested_release_page(vmx->nested.apic_access_page); + vmx->nested.apic_access_page = 0; + } nested_free_all_saved_vmcss(vmx); } @@ -5810,6 +5852,243 @@ static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry) { } +/* + * prepare_vmcs02 is called when the L1 guest hypervisor runs its nested + * L2 guest. L1 has a vmcs for L2 (vmcs12), and this function "merges" it + * with L0's requirements for its guest (a.k.a. vmsc01), so we can run the L2 + * guest in a way that will both be appropriate to L1's requests, and our + * needs. In addition to modifying the active vmcs (which is vmcs02), this + * function also has additional necessary side-effects, like setting various + * vcpu->arch fields. + */ +static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + u32 exec_control; + + vmcs_write16(GUEST_ES_SELECTOR, vmcs12->guest_es_selector); + vmcs_write16(GUEST_CS_SELECTOR, vmcs12->guest_cs_selector); + vmcs_write16(GUEST_SS_SELECTOR, vmcs12->guest_ss_selector); + vmcs_write16(GUEST_DS_SELECTOR, vmcs12->guest_ds_selector); + vmcs_write16(GUEST_FS_SELECTOR, vmcs12->guest_fs_selector); + vmcs_write16(GUEST_GS_SELECTOR, vmcs12->guest_gs_selector); + vmcs_write16(GUEST_LDTR_SELECTOR, vmcs12->guest_ldtr_selector); + vmcs_write16(GUEST_TR_SELECTOR, vmcs12->guest_tr_selector); + vmcs_write32(GUEST_ES_LIMIT, vmcs12->guest_es_limit); + vmcs_write32(GUEST_CS_LIMIT, vmcs12->guest_cs_limit); + vmcs_write32(GUEST_SS_LIMIT, vmcs12->guest_ss_limit); + vmcs_write32(GUEST_DS_LIMIT, vmcs12->guest_ds_limit); + vmcs_write32(GUEST_FS_LIMIT, vmcs12->guest_fs_limit); + vmcs_write32(GUEST_GS_LIMIT, vmcs12->guest_gs_limit); + vmcs_write32(GUEST_LDTR_LIMIT, vmcs12->guest_ldtr_limit); + vmcs_write32(GUEST_TR_LIMIT, vmcs12->guest_tr_limit); + vmcs_write32(GUEST_GDTR_LIMIT, vmcs12->guest_gdtr_limit); + vmcs_write32(GUEST_IDTR_LIMIT, vmcs12->guest_idtr_limit); + vmcs_write32(GUEST_ES_AR_BYTES, vmcs12->guest_es_ar_bytes); + vmcs_write32(GUEST_CS_AR_BYTES, vmcs12->guest_cs_ar_bytes); + vmcs_write32(GUEST_SS_AR_BYTES, vmcs12->guest_ss_ar_bytes); + vmcs_write32(GUEST_DS_AR_BYTES, vmcs12->guest_ds_ar_bytes); + vmcs_write32(GUEST_FS_AR_BYTES, vmcs12->guest_fs_ar_bytes); + vmcs_write32(GUEST_GS_AR_BYTES, vmcs12->guest_gs_ar_bytes); + vmcs_write32(GUEST_LDTR_AR_BYTES, vmcs12->guest_ldtr_ar_bytes); + vmcs_write32(GUEST_TR_AR_BYTES, vmcs12->guest_tr_ar_bytes); + vmcs_writel(GUEST_ES_BASE, vmcs12->guest_es_base); + vmcs_writel(GUEST_CS_BASE, vmcs12->guest_cs_base); + vmcs_writel(GUEST_SS_BASE, vmcs12->guest_ss_base); + vmcs_writel(GUEST_DS_BASE, vmcs12->guest_ds_base); + vmcs_writel(GUEST_FS_BASE, vmcs12->guest_fs_base); + vmcs_writel(GUEST_GS_BASE, vmcs12->guest_gs_base); + vmcs_writel(GUEST_LDTR_BASE, vmcs12->guest_ldtr_base); + vmcs_writel(GUEST_TR_BASE, vmcs12->guest_tr_base); + vmcs_writel(GUEST_GDTR_BASE, vmcs12->guest_gdtr_base); + vmcs_writel(GUEST_IDTR_BASE, vmcs12->guest_idtr_base); + + vmcs_write64(GUEST_IA32_DEBUGCTL, vmcs12->guest_ia32_debugctl); + vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, + vmcs12->vm_entry_intr_info_field); + vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, + vmcs12->vm_entry_exception_error_code); + vmcs_write32(VM_ENTRY_INSTRUCTION_LEN, + vmcs12->vm_entry_instruction_len); + vmcs_write32(GUEST_INTERRUPTIBILITY_INFO, + vmcs12->guest_interruptibility_info); + vmcs_write32(GUEST_ACTIVITY_STATE, vmcs12->guest_activity_state); + vmcs_write32(GUEST_SYSENTER_CS, vmcs12->guest_sysenter_cs); + vmcs_writel(GUEST_DR7, vmcs12->guest_dr7); + vmcs_writel(GUEST_RFLAGS, vmcs12->guest_rflags); + vmcs_writel(GUEST_PENDING_DBG_EXCEPTIONS, + vmcs12->guest_pending_dbg_exceptions); + vmcs_writel(GUEST_SYSENTER_ESP, vmcs12->guest_sysenter_esp); + vmcs_writel(GUEST_SYSENTER_EIP, vmcs12->guest_sysenter_eip); + + vmcs_write64(VMCS_LINK_POINTER, -1ull); + + vmcs_write32(PIN_BASED_VM_EXEC_CONTROL, + (vmcs_config.pin_based_exec_ctrl | + vmcs12->pin_based_vm_exec_control)); + + /* + * Whether page-faults are trapped is determined by a combination of + * 3 settings: PFEC_MASK, PFEC_MATCH and EXCEPTION_BITMAP.PF. + * If enable_ept, L0 doesn't care about page faults and we should + * set all of these to L1's desires. However, if !enable_ept, L0 does + * care about (at least some) page faults, and because it is not easy + * (if at all possible?) to merge L0 and L1's desires, we simply ask + * to exit on each and every L2 page fault. This is done by setting + * MASK=MATCH=0 and (see below) EB.PF=1. + * Note that below we don't need special code to set EB.PF beyond the + * "or"ing of the EB of vmcs01 and vmcs12, because when enable_ept, + * vmcs01's EB.PF is 0 so the "or" will take vmcs12's value, and when + * !enable_ept, EB.PF is 1, so the "or" will always be 1. + * + * A problem with this approach (when !enable_ept) is that L1 may be + * injected with more page faults than it asked for. This could have + * caused problems, but in practice existing hypervisors don't care. + * To fix this, we will need to emulate the PFEC checking (on the L1 + * page tables), using walk_addr(), when injecting PFs to L1. + */ + vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, + enable_ept ? vmcs12->page_fault_error_code_mask : 0); + vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, + enable_ept ? vmcs12->page_fault_error_code_match : 0); + + if (cpu_has_secondary_exec_ctrls()) { + u32 exec_control = vmx_secondary_exec_control(vmx); + if (!vmx->rdtscp_enabled) + exec_control &= ~SECONDARY_EXEC_RDTSCP; + /* Take the following fields only from vmcs12 */ + exec_control &= ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES; + if (nested_cpu_has(vmcs12, + CPU_BASED_ACTIVATE_SECONDARY_CONTROLS)) + exec_control |= vmcs12->secondary_vm_exec_control; + + if (exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES) { + /* + * Translate L1 physical address to host physical + * address for vmcs02. Keep the page pinned, so this + * physical address remains valid. We keep a reference + * to it so we can release it later. + */ + if (vmx->nested.apic_access_page) /* shouldn't happen */ + nested_release_page(vmx->nested.apic_access_page); + vmx->nested.apic_access_page = + nested_get_page(vcpu, vmcs12->apic_access_addr); + /* + * If translation failed, no matter: This feature asks + * to exit when accessing the given address, and if it + * can never be accessed, this feature won't do + * anything anyway. + */ + if (!vmx->nested.apic_access_page) + exec_control &= + ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES; + else + vmcs_write64(APIC_ACCESS_ADDR, + page_to_phys(vmx->nested.apic_access_page)); + } + + vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control); + } + + + /* + * Set host-state according to L0's settings (vmcs12 is irrelevant here) + * Some constant fields are set here by vmx_set_constant_host_state(). + * Other fields are different per CPU, and will be set later when + * vmx_vcpu_load() is called, and when vmx_save_host_state() is called. + */ + vmx_set_constant_host_state(); + + /* + * HOST_RSP is normally set correctly in vmx_vcpu_run() just before + * entry, but only if the current (host) sp changed from the value + * we wrote last (vmx->host_rsp). This cache is no longer relevant + * if we switch vmcs, and rather than hold a separate cache per vmcs, + * here we just force the write to happen on entry. + */ + vmx->host_rsp = 0; + + exec_control = vmx_exec_control(vmx); /* L0's desires */ + exec_control &= ~CPU_BASED_VIRTUAL_INTR_PENDING; + exec_control &= ~CPU_BASED_VIRTUAL_NMI_PENDING; + exec_control &= ~CPU_BASED_TPR_SHADOW; + exec_control |= vmcs12->cpu_based_vm_exec_control; + /* + * Merging of IO and MSR bitmaps not currently supported. + * Rather, exit every time. + */ + exec_control &= ~CPU_BASED_USE_MSR_BITMAPS; + exec_control &= ~CPU_BASED_USE_IO_BITMAPS; + exec_control |= CPU_BASED_UNCOND_IO_EXITING; + + vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, exec_control); + + /* EXCEPTION_BITMAP and CR0_GUEST_HOST_MASK should basically be the + * bitwise-or of what L1 wants to trap for L2, and what we want to + * trap. Note that CR0.TS also needs updating - we do this later. + */ + update_exception_bitmap(vcpu); + vcpu->arch.cr0_guest_owned_bits &= ~vmcs12->cr0_guest_host_mask; + vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits); + + /* Note: IA32_MODE, LOAD_IA32_EFER are modified by vmx_set_efer below */ + vmcs_write32(VM_EXIT_CONTROLS, + vmcs12->vm_exit_controls | vmcs_config.vmexit_ctrl); + vmcs_write32(VM_ENTRY_CONTROLS, vmcs12->vm_entry_controls | + (vmcs_config.vmentry_ctrl & ~VM_ENTRY_IA32E_MODE)); + + if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT) + vmcs_write64(GUEST_IA32_PAT, vmcs12->guest_ia32_pat); + else if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) + vmcs_write64(GUEST_IA32_PAT, vmx->vcpu.arch.pat); + + + set_cr4_guest_host_mask(vmx); + + vmcs_write64(TSC_OFFSET, + vmx->nested.vmcs01_tsc_offset + vmcs12->tsc_offset); + + if (enable_vpid) { + /* + * Trivially support vpid by letting L2s share their parent + * L1's vpid. TODO: move to a more elaborate solution, giving + * each L2 its own vpid and exposing the vpid feature to L1. + */ + vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid); + vmx_flush_tlb(vcpu); + } + + if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER) + vcpu->arch.efer = vmcs12->guest_ia32_efer; + if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) + vcpu->arch.efer |= (EFER_LMA | EFER_LME); + else + vcpu->arch.efer &= ~(EFER_LMA | EFER_LME); + /* Note: modifies VM_ENTRY/EXIT_CONTROLS and GUEST/HOST_IA32_EFER */ + vmx_set_efer(vcpu, vcpu->arch.efer); + + /* + * This sets GUEST_CR0 to vmcs12->guest_cr0, with possibly a modified + * TS bit (for lazy fpu) and bits which we consider mandatory enabled. + * The CR0_READ_SHADOW is what L2 should have expected to read given + * the specifications by L1; It's not enough to take + * vmcs12->cr0_read_shadow because on our cr0_guest_host_mask we we + * have more bits than L1 expected. + */ + vmx_set_cr0(vcpu, vmcs12->guest_cr0); + vmcs_writel(CR0_READ_SHADOW, nested_read_cr0(vmcs12)); + + vmx_set_cr4(vcpu, vmcs12->guest_cr4); + vmcs_writel(CR4_READ_SHADOW, nested_read_cr4(vmcs12)); + + /* shadow page tables on either EPT or shadow page tables */ + kvm_set_cr3(vcpu, vmcs12->guest_cr3); + kvm_mmu_reset_context(vcpu); + + kvm_register_write(vcpu, VCPU_REGS_RSP, vmcs12->guest_rsp); + kvm_register_write(vcpu, VCPU_REGS_RIP, vmcs12->guest_rip); +} + static int vmx_check_intercept(struct kvm_vcpu *vcpu, struct x86_instruction_info *info, enum x86_intercept_stage stage)