svm->vmcb will now point to either a separate vmcb L1 ( not nested ) or L2 vmcb 
( nested ).

Issues:

1) There is some wholesale copying of vmcb.save and vmcb.contol
   areas which will need to be refined.

2) There is a workaround in nested_svm_vmexit() where

   if (svm->vmcb01->control.asid == 0)
       svm->vmcb01->control.asid = svm->nested.vmcb02->control.asid;

   This was done as a result of the kvm selftest 'state_test'. In that
   test svm_set_nested_state() is called before svm_vcpu_run().
   The asid is assigned by svm_vcpu_run -> pre_svm_run for the current
   vmcb which is now vmcb02 as we are in nested mode subsequently
   vmcb01.control.asid is never set as it should be.

Tested:
kvm-unit-tests
kvm self tests

Signed-off-by: Cathy Avery <cav...@redhat.com>
---
 arch/x86/kvm/svm/nested.c | 116 ++++++++++++++++++--------------------
 arch/x86/kvm/svm/svm.c    |  41 +++++++-------
 arch/x86/kvm/svm/svm.h    |  10 ++--
 3 files changed, 81 insertions(+), 86 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index e90bc436f584..0a06e62010d8 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -75,12 +75,12 @@ static unsigned long nested_svm_get_tdp_cr3(struct kvm_vcpu 
*vcpu)
 static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
 {
        struct vcpu_svm *svm = to_svm(vcpu);
-       struct vmcb *hsave = svm->nested.hsave;
 
        WARN_ON(mmu_is_nested(vcpu));
 
        vcpu->arch.mmu = &vcpu->arch.guest_mmu;
-       kvm_init_shadow_npt_mmu(vcpu, X86_CR0_PG, hsave->save.cr4, 
hsave->save.efer,
+       kvm_init_shadow_npt_mmu(vcpu, X86_CR0_PG, svm->vmcb01->save.cr4,
+                               svm->vmcb01->save.efer,
                                svm->nested.ctl.nested_cr3);
        vcpu->arch.mmu->get_guest_pgd     = nested_svm_get_tdp_cr3;
        vcpu->arch.mmu->get_pdptr         = nested_svm_get_tdp_pdptr;
@@ -105,7 +105,7 @@ void recalc_intercepts(struct vcpu_svm *svm)
                return;
 
        c = &svm->vmcb->control;
-       h = &svm->nested.hsave->control;
+       h = &svm->vmcb01->control;
        g = &svm->nested.ctl;
 
        svm->nested.host_intercept_exceptions = h->intercept_exceptions;
@@ -403,7 +403,7 @@ static void nested_prepare_vmcb_control(struct vcpu_svm 
*svm)
 
        svm->vmcb->control.int_ctl             =
                (svm->nested.ctl.int_ctl & ~mask) |
-               (svm->nested.hsave->control.int_ctl & mask);
+               (svm->vmcb01->control.int_ctl & mask);
 
        svm->vmcb->control.virt_ext            = svm->nested.ctl.virt_ext;
        svm->vmcb->control.int_vector          = svm->nested.ctl.int_vector;
@@ -432,6 +432,12 @@ int enter_svm_guest_mode(struct vcpu_svm *svm, u64 
vmcb_gpa,
        int ret;
 
        svm->nested.vmcb = vmcb_gpa;
+
+       WARN_ON(svm->vmcb == svm->nested.vmcb02);
+
+       svm->nested.vmcb02->control = svm->vmcb01->control;
+       svm->vmcb = svm->nested.vmcb02;
+       svm->vmcb_pa = svm->nested.vmcb02_pa;
        load_nested_vmcb_control(svm, &nested_vmcb->control);
        nested_prepare_vmcb_save(svm, nested_vmcb);
        nested_prepare_vmcb_control(svm);
@@ -450,8 +456,6 @@ int nested_svm_vmrun(struct vcpu_svm *svm)
 {
        int ret;
        struct vmcb *nested_vmcb;
-       struct vmcb *hsave = svm->nested.hsave;
-       struct vmcb *vmcb = svm->vmcb;
        struct kvm_host_map map;
        u64 vmcb_gpa;
 
@@ -496,29 +500,17 @@ int nested_svm_vmrun(struct vcpu_svm *svm)
        kvm_clear_exception_queue(&svm->vcpu);
        kvm_clear_interrupt_queue(&svm->vcpu);
 
-       /*
-        * Save the old vmcb, so we don't need to pick what we save, but can
-        * restore everything when a VMEXIT occurs
-        */
-       hsave->save.es     = vmcb->save.es;
-       hsave->save.cs     = vmcb->save.cs;
-       hsave->save.ss     = vmcb->save.ss;
-       hsave->save.ds     = vmcb->save.ds;
-       hsave->save.gdtr   = vmcb->save.gdtr;
-       hsave->save.idtr   = vmcb->save.idtr;
-       hsave->save.efer   = svm->vcpu.arch.efer;
-       hsave->save.cr0    = kvm_read_cr0(&svm->vcpu);
-       hsave->save.cr4    = svm->vcpu.arch.cr4;
-       hsave->save.rflags = kvm_get_rflags(&svm->vcpu);
-       hsave->save.rip    = kvm_rip_read(&svm->vcpu);
-       hsave->save.rsp    = vmcb->save.rsp;
-       hsave->save.rax    = vmcb->save.rax;
-       if (npt_enabled)
-               hsave->save.cr3    = vmcb->save.cr3;
-       else
-               hsave->save.cr3    = kvm_read_cr3(&svm->vcpu);
-
-       copy_vmcb_control_area(&hsave->control, &vmcb->control);
+
+       /* Update vmcb0. We will restore everything when a VMEXIT occurs */
+
+       svm->vmcb01->save.efer   = svm->vcpu.arch.efer;
+       svm->vmcb01->save.cr0    = kvm_read_cr0(&svm->vcpu);
+       svm->vmcb01->save.cr4    = svm->vcpu.arch.cr4;
+       svm->vmcb01->save.rflags = kvm_get_rflags(&svm->vcpu);
+       svm->vmcb01->save.rip    = kvm_rip_read(&svm->vcpu);
+
+       if (!npt_enabled)
+               svm->vmcb01->save.cr3 = kvm_read_cr3(&svm->vcpu);
 
        svm->nested.nested_run_pending = 1;
 
@@ -564,7 +556,6 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 {
        int rc;
        struct vmcb *nested_vmcb;
-       struct vmcb *hsave = svm->nested.hsave;
        struct vmcb *vmcb = svm->vmcb;
        struct kvm_host_map map;
 
@@ -628,8 +619,11 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
        nested_vmcb->control.pause_filter_thresh =
                svm->vmcb->control.pause_filter_thresh;
 
-       /* Restore the original control entries */
-       copy_vmcb_control_area(&vmcb->control, &hsave->control);
+       if (svm->vmcb01->control.asid == 0)
+               svm->vmcb01->control.asid = svm->nested.vmcb02->control.asid;
+
+       svm->vmcb = svm->vmcb01;
+       svm->vmcb_pa = svm->nested.vmcb01_pa;
 
        /* On vmexit the  GIF is set to false */
        svm_set_gif(svm, false);
@@ -640,19 +634,13 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
        svm->nested.ctl.nested_cr3 = 0;
 
        /* Restore selected save entries */
-       svm->vmcb->save.es = hsave->save.es;
-       svm->vmcb->save.cs = hsave->save.cs;
-       svm->vmcb->save.ss = hsave->save.ss;
-       svm->vmcb->save.ds = hsave->save.ds;
-       svm->vmcb->save.gdtr = hsave->save.gdtr;
-       svm->vmcb->save.idtr = hsave->save.idtr;
-       kvm_set_rflags(&svm->vcpu, hsave->save.rflags);
-       svm_set_efer(&svm->vcpu, hsave->save.efer);
-       svm_set_cr0(&svm->vcpu, hsave->save.cr0 | X86_CR0_PE);
-       svm_set_cr4(&svm->vcpu, hsave->save.cr4);
-       kvm_rax_write(&svm->vcpu, hsave->save.rax);
-       kvm_rsp_write(&svm->vcpu, hsave->save.rsp);
-       kvm_rip_write(&svm->vcpu, hsave->save.rip);
+       kvm_set_rflags(&svm->vcpu, svm->vmcb->save.rflags);
+       svm_set_efer(&svm->vcpu, svm->vmcb->save.efer);
+       svm_set_cr0(&svm->vcpu, svm->vmcb->save.cr0 | X86_CR0_PE);
+       svm_set_cr4(&svm->vcpu, svm->vmcb->save.cr4);
+       kvm_rax_write(&svm->vcpu, svm->vmcb->save.rax);
+       kvm_rsp_write(&svm->vcpu, svm->vmcb->save.rsp);
+       kvm_rip_write(&svm->vcpu, svm->vmcb->save.rip);
        svm->vmcb->save.dr7 = 0;
        svm->vmcb->save.cpl = 0;
        svm->vmcb->control.exit_int_info = 0;
@@ -670,12 +658,12 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 
        nested_svm_uninit_mmu_context(&svm->vcpu);
 
-       rc = nested_svm_load_cr3(&svm->vcpu, hsave->save.cr3, false);
+       rc = nested_svm_load_cr3(&svm->vcpu, svm->vmcb->save.cr3, false);
        if (rc)
                return 1;
 
-       if (npt_enabled)
-               svm->vmcb->save.cr3 = hsave->save.cr3;
+       if (!npt_enabled)
+               svm->vmcb01->save.cr3 = kvm_read_cr3(&svm->vcpu);
 
        /*
         * Drop what we picked up for L2 via svm_complete_interrupts() so it
@@ -694,12 +682,10 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 void svm_leave_nested(struct vcpu_svm *svm)
 {
        if (is_guest_mode(&svm->vcpu)) {
-               struct vmcb *hsave = svm->nested.hsave;
-               struct vmcb *vmcb = svm->vmcb;
-
                svm->nested.nested_run_pending = 0;
                leave_guest_mode(&svm->vcpu);
-               copy_vmcb_control_area(&vmcb->control, &hsave->control);
+               svm->vmcb = svm->vmcb01;
+               svm->vmcb_pa = svm->nested.vmcb01_pa;
                nested_svm_uninit_mmu_context(&svm->vcpu);
        }
 }
@@ -1046,10 +1032,9 @@ static int svm_get_nested_state(struct kvm_vcpu *vcpu,
        if (copy_to_user(&user_vmcb->control, &svm->nested.ctl,
                         sizeof(user_vmcb->control)))
                return -EFAULT;
-       if (copy_to_user(&user_vmcb->save, &svm->nested.hsave->save,
+       if (copy_to_user(&user_vmcb->save, &svm->vmcb01->save,
                         sizeof(user_vmcb->save)))
                return -EFAULT;
-
 out:
        return kvm_state.size;
 }
@@ -1059,7 +1044,6 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
                                struct kvm_nested_state *kvm_state)
 {
        struct vcpu_svm *svm = to_svm(vcpu);
-       struct vmcb *hsave = svm->nested.hsave;
        struct vmcb __user *user_vmcb = (struct vmcb __user *)
                &user_kvm_nested_state->data.svm[0];
        struct vmcb_control_area ctl;
@@ -1121,16 +1105,24 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
        if (!(save.cr0 & X86_CR0_PG))
                return -EINVAL;
 
+       svm->nested.vmcb02->control = svm->vmcb01->control;
+       svm->nested.vmcb02->save = svm->vmcb01->save;
+       svm->vmcb01->save = save;
+
+       WARN_ON(svm->vmcb == svm->nested.vmcb02);
+
+       svm->nested.vmcb = kvm_state->hdr.svm.vmcb_pa;
+
+       svm->vmcb = svm->nested.vmcb02;
+       svm->vmcb_pa = svm->nested.vmcb02_pa;
+
        /*
-        * All checks done, we can enter guest mode.  L1 control fields
-        * come from the nested save state.  Guest state is already
-        * in the registers, the save area of the nested state instead
-        * contains saved L1 state.
+        * All checks done, we can enter guest mode. L2 control fields will
+        * be the result of a combination of L1 and userspace indicated
+        * L12.control. The save area of L1 vmcb now contains the userspace
+        * indicated L1.save.
         */
-       copy_vmcb_control_area(&hsave->control, &svm->vmcb->control);
-       hsave->save = save;
 
-       svm->nested.vmcb = kvm_state->hdr.svm.vmcb_pa;
        load_nested_vmcb_control(svm, &ctl);
        nested_prepare_vmcb_control(svm);
 
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 5764b87379cf..d8022f989ffb 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -971,8 +971,8 @@ static u64 svm_write_l1_tsc_offset(struct kvm_vcpu *vcpu, 
u64 offset)
        if (is_guest_mode(vcpu)) {
                /* Write L1's TSC offset.  */
                g_tsc_offset = svm->vmcb->control.tsc_offset -
-                              svm->nested.hsave->control.tsc_offset;
-               svm->nested.hsave->control.tsc_offset = offset;
+                              svm->vmcb01->control.tsc_offset;
+               svm->vmcb01->control.tsc_offset = offset;
        }
 
        trace_kvm_write_tsc_offset(vcpu->vcpu_id,
@@ -1171,9 +1171,9 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool 
init_event)
 static int svm_create_vcpu(struct kvm_vcpu *vcpu)
 {
        struct vcpu_svm *svm;
-       struct page *page;
+       struct page *vmcb01_page;
+       struct page *vmcb02_page;
        struct page *msrpm_pages;
-       struct page *hsave_page;
        struct page *nested_msrpm_pages;
        int err;
 
@@ -1181,8 +1181,8 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
        svm = to_svm(vcpu);
 
        err = -ENOMEM;
-       page = alloc_page(GFP_KERNEL_ACCOUNT);
-       if (!page)
+       vmcb01_page = alloc_page(GFP_KERNEL_ACCOUNT);
+       if (!vmcb01_page)
                goto out;
 
        msrpm_pages = alloc_pages(GFP_KERNEL_ACCOUNT, MSRPM_ALLOC_ORDER);
@@ -1193,8 +1193,8 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
        if (!nested_msrpm_pages)
                goto free_page2;
 
-       hsave_page = alloc_page(GFP_KERNEL_ACCOUNT);
-       if (!hsave_page)
+       vmcb02_page = alloc_page(GFP_KERNEL_ACCOUNT);
+       if (!vmcb02_page)
                goto free_page3;
 
        err = avic_init_vcpu(svm);
@@ -1207,8 +1207,9 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
        if (irqchip_in_kernel(vcpu->kvm) && kvm_apicv_activated(vcpu->kvm))
                svm->avic_is_running = true;
 
-       svm->nested.hsave = page_address(hsave_page);
-       clear_page(svm->nested.hsave);
+       svm->nested.vmcb02 = page_address(vmcb02_page);
+       clear_page(svm->nested.vmcb02);
+       svm->nested.vmcb02_pa = __sme_set(page_to_pfn(vmcb02_page) << 
PAGE_SHIFT);
 
        svm->msrpm = page_address(msrpm_pages);
        svm_vcpu_init_msrpm(svm->msrpm);
@@ -1216,9 +1217,11 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
        svm->nested.msrpm = page_address(nested_msrpm_pages);
        svm_vcpu_init_msrpm(svm->nested.msrpm);
 
-       svm->vmcb = page_address(page);
+       svm->vmcb = svm->vmcb01 = page_address(vmcb01_page);
        clear_page(svm->vmcb);
-       svm->vmcb_pa = __sme_set(page_to_pfn(page) << PAGE_SHIFT);
+       svm->vmcb_pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT);
+       svm->nested.vmcb01_pa = svm->vmcb_pa;
+
        svm->asid_generation = 0;
        init_vmcb(svm);
 
@@ -1228,13 +1231,13 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
        return 0;
 
 free_page4:
-       __free_page(hsave_page);
+       __free_page(vmcb02_page);
 free_page3:
        __free_pages(nested_msrpm_pages, MSRPM_ALLOC_ORDER);
 free_page2:
        __free_pages(msrpm_pages, MSRPM_ALLOC_ORDER);
 free_page1:
-       __free_page(page);
+       __free_page(vmcb01_page);
 out:
        return err;
 }
@@ -1256,11 +1259,11 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu)
         * svm_vcpu_load(). So, ensure that no logical CPU has this
         * vmcb page recorded as its current vmcb.
         */
-       svm_clear_current_vmcb(svm->vmcb);
 
-       __free_page(pfn_to_page(__sme_clr(svm->vmcb_pa) >> PAGE_SHIFT));
+       svm_clear_current_vmcb(svm->vmcb);
+       __free_page(pfn_to_page(__sme_clr(svm->nested.vmcb01_pa) >> 
PAGE_SHIFT));
+       __free_page(pfn_to_page(__sme_clr(svm->nested.vmcb02_pa) >> 
PAGE_SHIFT));
        __free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER);
-       __free_page(virt_to_page(svm->nested.hsave));
        __free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER);
 }
 
@@ -1393,7 +1396,7 @@ static void svm_clear_vintr(struct vcpu_svm *svm)
        /* Drop int_ctl fields related to VINTR injection.  */
        svm->vmcb->control.int_ctl &= mask;
        if (is_guest_mode(&svm->vcpu)) {
-               svm->nested.hsave->control.int_ctl &= mask;
+               svm->vmcb01->control.int_ctl &= mask;
 
                WARN_ON((svm->vmcb->control.int_ctl & V_TPR_MASK) !=
                        (svm->nested.ctl.int_ctl & V_TPR_MASK));
@@ -3127,7 +3130,7 @@ bool svm_interrupt_blocked(struct kvm_vcpu *vcpu)
        if (is_guest_mode(vcpu)) {
                /* As long as interrupts are being delivered...  */
                if ((svm->nested.ctl.int_ctl & V_INTR_MASKING_MASK)
-                   ? !(svm->nested.hsave->save.rflags & X86_EFLAGS_IF)
+                   ? !(svm->vmcb01->save.rflags & X86_EFLAGS_IF)
                    : !(kvm_get_rflags(vcpu) & X86_EFLAGS_IF))
                        return true;
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index a798e1731709..e908b83bfa69 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -82,7 +82,9 @@ struct kvm_svm {
 struct kvm_vcpu;
 
 struct svm_nested_state {
-       struct vmcb *hsave;
+       struct vmcb *vmcb02;
+       unsigned long vmcb01_pa;
+       unsigned long vmcb02_pa;
        u64 hsave_msr;
        u64 vm_cr_msr;
        u64 vmcb;
@@ -102,6 +104,7 @@ struct svm_nested_state {
 struct vcpu_svm {
        struct kvm_vcpu vcpu;
        struct vmcb *vmcb;
+       struct vmcb *vmcb01;
        unsigned long vmcb_pa;
        struct svm_cpu_data *svm_data;
        uint64_t asid_generation;
@@ -208,10 +211,7 @@ static inline struct vcpu_svm *to_svm(struct kvm_vcpu 
*vcpu)
 
 static inline struct vmcb *get_host_vmcb(struct vcpu_svm *svm)
 {
-       if (is_guest_mode(&svm->vcpu))
-               return svm->nested.hsave;
-       else
-               return svm->vmcb;
+       return svm->vmcb01;
 }
 
 static inline void set_cr_intercept(struct vcpu_svm *svm, int bit)
-- 
2.20.1

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