KVM: VMX: Add facility to atomically switch MSRs on guest entry/exit
Some guest msr values cannot be used on the host (for example. EFER.NX=0), so we need to switch them atomically during guest entry or exit. Add a facility to program the vmx msr autoload registers accordingly. Signed-off-by: Avi Kivity <avi@redhat.com>hifive-unleashed-5.1
parent
5dfa3d170e
commit
61d2ef2ce3
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@ -98,6 +98,8 @@ module_param(ple_gap, int, S_IRUGO);
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static int ple_window = KVM_VMX_DEFAULT_PLE_WINDOW;
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static int ple_window = KVM_VMX_DEFAULT_PLE_WINDOW;
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module_param(ple_window, int, S_IRUGO);
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module_param(ple_window, int, S_IRUGO);
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#define NR_AUTOLOAD_MSRS 1
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struct vmcs {
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struct vmcs {
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u32 revision_id;
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u32 revision_id;
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u32 abort;
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u32 abort;
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@ -125,6 +127,11 @@ struct vcpu_vmx {
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u64 msr_guest_kernel_gs_base;
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u64 msr_guest_kernel_gs_base;
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#endif
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#endif
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struct vmcs *vmcs;
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struct vmcs *vmcs;
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struct msr_autoload {
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unsigned nr;
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struct vmx_msr_entry guest[NR_AUTOLOAD_MSRS];
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struct vmx_msr_entry host[NR_AUTOLOAD_MSRS];
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} msr_autoload;
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struct {
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struct {
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int loaded;
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int loaded;
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u16 fs_sel, gs_sel, ldt_sel;
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u16 fs_sel, gs_sel, ldt_sel;
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@ -595,6 +602,46 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
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vmcs_write32(EXCEPTION_BITMAP, eb);
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vmcs_write32(EXCEPTION_BITMAP, eb);
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}
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}
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static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr)
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{
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unsigned i;
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struct msr_autoload *m = &vmx->msr_autoload;
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for (i = 0; i < m->nr; ++i)
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if (m->guest[i].index == msr)
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break;
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if (i == m->nr)
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return;
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--m->nr;
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m->guest[i] = m->guest[m->nr];
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m->host[i] = m->host[m->nr];
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vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->nr);
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vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr);
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}
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static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
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u64 guest_val, u64 host_val)
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{
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unsigned i;
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struct msr_autoload *m = &vmx->msr_autoload;
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for (i = 0; i < m->nr; ++i)
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if (m->guest[i].index == msr)
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break;
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if (i == m->nr) {
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++m->nr;
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vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->nr);
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vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr);
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}
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m->guest[i].index = msr;
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m->guest[i].value = guest_val;
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m->host[i].index = msr;
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m->host[i].value = host_val;
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}
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static void reload_tss(void)
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static void reload_tss(void)
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{
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{
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/*
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/*
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@ -2470,7 +2517,9 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
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vmcs_writel(HOST_RIP, kvm_vmx_return); /* 22.2.5 */
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vmcs_writel(HOST_RIP, kvm_vmx_return); /* 22.2.5 */
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vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0);
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vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0);
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vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, 0);
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vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, 0);
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vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host));
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vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, 0);
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vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, 0);
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vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest));
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rdmsr(MSR_IA32_SYSENTER_CS, host_sysenter_cs, junk);
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rdmsr(MSR_IA32_SYSENTER_CS, host_sysenter_cs, junk);
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vmcs_write32(HOST_IA32_SYSENTER_CS, host_sysenter_cs);
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vmcs_write32(HOST_IA32_SYSENTER_CS, host_sysenter_cs);
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