9f1d723ebd
(generated with debian/scripts/import-upstream-tag) Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
181 lines
6.4 KiB
Diff
181 lines
6.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Maxim Levitsky <mlevitsk@redhat.com>
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Date: Wed, 3 Aug 2022 18:50:11 +0300
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Subject: [PATCH] KVM: x86: emulator/smm: preserve interrupt shadow in SMRAM
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When #SMI is asserted, the CPU can be in interrupt shadow
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due to sti or mov ss.
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It is not mandatory in Intel/AMD prm to have the #SMI
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blocked during the shadow, and on top of
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that, since neither SVM nor VMX has true support for SMI
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window, waiting for one instruction would mean single stepping
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the guest.
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Instead, allow #SMI in this case, but both reset the interrupt
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window and stash its value in SMRAM to restore it on exit
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from SMM.
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This fixes rare failures seen mostly on windows guests on VMX,
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when #SMI falls on the sti instruction which mainfest in
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VM entry failure due to EFLAGS.IF not being set, but STI interrupt
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window still being set in the VMCS.
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Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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arch/x86/kvm/emulate.c | 17 ++++++++++++++---
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arch/x86/kvm/kvm_emulate.h | 10 ++++++----
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arch/x86/kvm/x86.c | 12 ++++++++++++
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3 files changed, 32 insertions(+), 7 deletions(-)
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diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
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index eb2f5e43f6add..7f5710c34f4e3 100644
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--- a/arch/x86/kvm/emulate.c
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+++ b/arch/x86/kvm/emulate.c
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@@ -2419,7 +2419,7 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt,
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const struct kvm_smram_state_32 *smstate)
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{
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struct desc_ptr dt;
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- int i;
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+ int i, r;
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ctxt->eflags = smstate->eflags | X86_EFLAGS_FIXED;
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ctxt->_eip = smstate->eip;
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@@ -2454,8 +2454,16 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt,
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ctxt->ops->set_smbase(ctxt, smstate->smbase);
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- return rsm_enter_protected_mode(ctxt, smstate->cr0,
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- smstate->cr3, smstate->cr4);
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+ r = rsm_enter_protected_mode(ctxt, smstate->cr0,
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+ smstate->cr3, smstate->cr4);
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+
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+ if (r != X86EMUL_CONTINUE)
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+ return r;
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+
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+ ctxt->ops->set_int_shadow(ctxt, 0);
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+ ctxt->interruptibility = (u8)smstate->int_shadow;
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+
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+ return X86EMUL_CONTINUE;
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}
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#ifdef CONFIG_X86_64
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@@ -2504,6 +2512,9 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt,
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rsm_load_seg_64(ctxt, &smstate->fs, VCPU_SREG_FS);
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rsm_load_seg_64(ctxt, &smstate->gs, VCPU_SREG_GS);
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+ ctxt->ops->set_int_shadow(ctxt, 0);
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+ ctxt->interruptibility = (u8)smstate->int_shadow;
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+
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return X86EMUL_CONTINUE;
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}
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#endif
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diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
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index 3b37b3e173791..a64c190abf28f 100644
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--- a/arch/x86/kvm/kvm_emulate.h
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+++ b/arch/x86/kvm/kvm_emulate.h
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@@ -231,6 +231,7 @@ struct x86_emulate_ops {
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bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt);
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void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked);
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+ void (*set_int_shadow)(struct x86_emulate_ctxt *ctxt, u8 shadow);
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unsigned (*get_hflags)(struct x86_emulate_ctxt *ctxt);
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void (*exiting_smm)(struct x86_emulate_ctxt *ctxt);
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@@ -497,7 +498,8 @@ struct kvm_smram_state_32 {
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u32 reserved1[62];
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u32 smbase;
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u32 smm_revision;
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- u32 reserved2[5];
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+ u32 reserved2[4];
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+ u32 int_shadow; /* KVM extension */
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u32 cr4; /* CR4 is not present in Intel/AMD SMRAM image */
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u32 reserved3[5];
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@@ -545,6 +547,7 @@ static inline void __check_smram32_offsets(void)
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__CHECK_SMRAM32_OFFSET(smbase, 0xFEF8);
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__CHECK_SMRAM32_OFFSET(smm_revision, 0xFEFC);
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__CHECK_SMRAM32_OFFSET(reserved2, 0xFF00);
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+ __CHECK_SMRAM32_OFFSET(int_shadow, 0xFF10);
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__CHECK_SMRAM32_OFFSET(cr4, 0xFF14);
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__CHECK_SMRAM32_OFFSET(reserved3, 0xFF18);
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__CHECK_SMRAM32_OFFSET(ds, 0xFF2C);
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@@ -604,7 +607,7 @@ struct kvm_smram_state_64 {
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u64 io_restart_rsi;
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u64 io_restart_rdi;
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u32 io_restart_dword;
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- u32 reserved1;
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+ u32 int_shadow;
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u8 io_inst_restart;
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u8 auto_hlt_restart;
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u8 reserved2[6];
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@@ -642,7 +645,6 @@ struct kvm_smram_state_64 {
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u64 gprs[16]; /* GPRS in a reversed "natural" X86 order (R15/R14/../RCX/RAX.) */
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};
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-
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static inline void __check_smram64_offsets(void)
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{
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#define __CHECK_SMRAM64_OFFSET(field, offset) \
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@@ -663,7 +665,7 @@ static inline void __check_smram64_offsets(void)
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__CHECK_SMRAM64_OFFSET(io_restart_rsi, 0xFEB0);
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__CHECK_SMRAM64_OFFSET(io_restart_rdi, 0xFEB8);
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__CHECK_SMRAM64_OFFSET(io_restart_dword, 0xFEC0);
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- __CHECK_SMRAM64_OFFSET(reserved1, 0xFEC4);
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+ __CHECK_SMRAM64_OFFSET(int_shadow, 0xFEC4);
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__CHECK_SMRAM64_OFFSET(io_inst_restart, 0xFEC8);
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__CHECK_SMRAM64_OFFSET(auto_hlt_restart, 0xFEC9);
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__CHECK_SMRAM64_OFFSET(reserved2, 0xFECA);
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diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
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index 28448379eabaa..df7b24fd7abcd 100644
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--- a/arch/x86/kvm/x86.c
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+++ b/arch/x86/kvm/x86.c
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@@ -7441,6 +7441,11 @@ static void emulator_set_nmi_mask(struct x86_emulate_ctxt *ctxt, bool masked)
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static_call(kvm_x86_set_nmi_mask)(emul_to_vcpu(ctxt), masked);
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}
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+static void emulator_set_int_shadow(struct x86_emulate_ctxt *ctxt, u8 shadow)
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+{
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+ static_call(kvm_x86_set_interrupt_shadow)(emul_to_vcpu(ctxt), shadow);
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+}
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+
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static unsigned emulator_get_hflags(struct x86_emulate_ctxt *ctxt)
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{
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return emul_to_vcpu(ctxt)->arch.hflags;
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@@ -7510,6 +7515,7 @@ static const struct x86_emulate_ops emulate_ops = {
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.guest_has_fxsr = emulator_guest_has_fxsr,
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.guest_has_rdpid = emulator_guest_has_rdpid,
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.set_nmi_mask = emulator_set_nmi_mask,
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+ .set_int_shadow = emulator_set_int_shadow,
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.get_hflags = emulator_get_hflags,
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.exiting_smm = emulator_exiting_smm,
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.leave_smm = emulator_leave_smm,
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@@ -9259,6 +9265,8 @@ static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, struct kvm_smram_stat
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smram->cr4 = kvm_read_cr4(vcpu);
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smram->smm_revision = 0x00020000;
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smram->smbase = vcpu->arch.smbase;
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+
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+ smram->int_shadow = static_call(kvm_x86_get_interrupt_shadow)(vcpu);
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}
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#ifdef CONFIG_X86_64
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@@ -9307,6 +9315,8 @@ static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, struct kvm_smram_stat
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enter_smm_save_seg_64(vcpu, &smram->ds, VCPU_SREG_DS);
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enter_smm_save_seg_64(vcpu, &smram->fs, VCPU_SREG_FS);
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enter_smm_save_seg_64(vcpu, &smram->gs, VCPU_SREG_GS);
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+
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+ smram->int_shadow = static_call(kvm_x86_get_interrupt_shadow)(vcpu);
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}
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#endif
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@@ -9343,6 +9353,8 @@ static void enter_smm(struct kvm_vcpu *vcpu)
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kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
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kvm_rip_write(vcpu, 0x8000);
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+ static_call(kvm_x86_set_interrupt_shadow)(vcpu, 0);
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+
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cr0 = vcpu->arch.cr0 & ~(X86_CR0_PE | X86_CR0_EM | X86_CR0_TS | X86_CR0_PG);
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static_call(kvm_x86_set_cr0)(vcpu, cr0);
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vcpu->arch.cr0 = cr0;
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