[PATCH RFC] KVM: x86: Allow some previously forbidden controls when eVMCS is in use

From: Vitaly Kuznetsov
Date: Wed Apr 20 2022 - 09:43:37 EST


Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
arch/x86/kvm/vmx/evmcs.h | 11 ++++-------
arch/x86/kvm/vmx/nested.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx/evmcs.h b/arch/x86/kvm/vmx/evmcs.h
index ddbdb557cc53..5963c6374db2 100644
--- a/arch/x86/kvm/vmx/evmcs.h
+++ b/arch/x86/kvm/vmx/evmcs.h
@@ -37,16 +37,14 @@ DECLARE_STATIC_KEY_FALSE(enable_evmcs);
* EPTP_LIST_ADDRESS = 0x00002024,
* VMREAD_BITMAP = 0x00002026,
* VMWRITE_BITMAP = 0x00002028,
- *
- * TSC_MULTIPLIER = 0x00002032,
* PLE_GAP = 0x00004020,
* PLE_WINDOW = 0x00004022,
* VMX_PREEMPTION_TIMER_VALUE = 0x0000482E,
- * GUEST_IA32_PERF_GLOBAL_CTRL = 0x00002808,
- * HOST_IA32_PERF_GLOBAL_CTRL = 0x00002c04,
*
- * Currently unsupported in KVM:
- * GUEST_IA32_RTIT_CTL = 0x00002814,
+ * While GUEST_IA32_PERF_GLOBAL_CTRL and HOST_IA32_PERF_GLOBAL_CTRL
+ * are present in eVMCSv1, Windows 11 still has issues booting when
+ * VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL/VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL
+ * are exposed to it, keep them filtered out.
*/
#define EVMCS1_UNSUPPORTED_PINCTRL (PIN_BASED_POSTED_INTR | \
PIN_BASED_VMX_PREEMPTION_TIMER)
@@ -57,7 +55,6 @@ DECLARE_STATIC_KEY_FALSE(enable_evmcs);
SECONDARY_EXEC_ENABLE_PML | \
SECONDARY_EXEC_ENABLE_VMFUNC | \
SECONDARY_EXEC_SHADOW_VMCS | \
- SECONDARY_EXEC_TSC_SCALING | \
SECONDARY_EXEC_PAUSE_LOOP_EXITING)
#define EVMCS1_UNSUPPORTED_VMEXIT_CTRL \
(VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL | \
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 3e2ef5edad4a..4a596973e505 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1628,6 +1628,10 @@ static void copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx, u32 hv_clean_fields
vmcs12->guest_rflags = evmcs->guest_rflags;
vmcs12->guest_interruptibility_info =
evmcs->guest_interruptibility_info;
+ /*
+ * Not present in struct vmcs12:
+ * vmcs12->guest_ssp = evmcs->guest_ssp;
+ */
}

if (unlikely(!(hv_clean_fields &
@@ -1674,6 +1678,13 @@ static void copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx, u32 hv_clean_fields
vmcs12->host_fs_selector = evmcs->host_fs_selector;
vmcs12->host_gs_selector = evmcs->host_gs_selector;
vmcs12->host_tr_selector = evmcs->host_tr_selector;
+ vmcs12->host_ia32_perf_global_ctrl = evmcs->host_ia32_perf_global_ctrl;
+ /*
+ * Not present in struct vmcs12:
+ * vmcs12->host_ia32_s_cet = evmcs->host_ia32_s_cet;
+ * vmcs12->host_ssp = evmcs->host_ssp;
+ * vmcs12->host_ia32_int_ssp_table_addr = evmcs->host_ia32_int_ssp_table_addr;
+ */
}

if (unlikely(!(hv_clean_fields &
@@ -1741,6 +1752,8 @@ static void copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx, u32 hv_clean_fields
vmcs12->tsc_offset = evmcs->tsc_offset;
vmcs12->virtual_apic_page_addr = evmcs->virtual_apic_page_addr;
vmcs12->xss_exit_bitmap = evmcs->xss_exit_bitmap;
+ vmcs12->encls_exiting_bitmap = evmcs->encls_exiting_bitmap;
+ vmcs12->tsc_multiplier = evmcs->tsc_multiplier;
}

if (unlikely(!(hv_clean_fields &
@@ -1788,6 +1801,13 @@ static void copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx, u32 hv_clean_fields
vmcs12->guest_bndcfgs = evmcs->guest_bndcfgs;
vmcs12->guest_activity_state = evmcs->guest_activity_state;
vmcs12->guest_sysenter_cs = evmcs->guest_sysenter_cs;
+ vmcs12->guest_ia32_perf_global_ctrl = evmcs->guest_ia32_perf_global_ctrl;
+ /*
+ * Not present in struct vmcs12:
+ * vmcs12->guest_ia32_s_cet = evmcs->guest_ia32_s_cet;
+ * vmcs12->guest_ia32_lbr_ctl = evmcs->guest_ia32_lbr_ctl;
+ * vmcs12->guest_ia32_int_ssp_table_addr = evmcs->guest_ia32_int_ssp_table_addr;
+ */
}

/*
@@ -1890,12 +1910,23 @@ static void copy_vmcs12_to_enlightened(struct vcpu_vmx *vmx)
* evmcs->vm_exit_msr_store_count = vmcs12->vm_exit_msr_store_count;
* evmcs->vm_exit_msr_load_count = vmcs12->vm_exit_msr_load_count;
* evmcs->vm_entry_msr_load_count = vmcs12->vm_entry_msr_load_count;
+ * evmcs->guest_ia32_perf_global_ctrl = vmcs12->guest_ia32_perf_global_ctrl;
+ * evmcs->host_ia32_perf_global_ctrl = vmcs12->host_ia32_perf_global_ctrl;
+ * evmcs->encls_exiting_bitmap = vmcs12->encls_exiting_bitmap;
+ * evmcs->tsc_multiplier = vmcs12->tsc_multiplier;
*
* Not present in struct vmcs12:
* evmcs->exit_io_instruction_ecx = vmcs12->exit_io_instruction_ecx;
* evmcs->exit_io_instruction_esi = vmcs12->exit_io_instruction_esi;
* evmcs->exit_io_instruction_edi = vmcs12->exit_io_instruction_edi;
* evmcs->exit_io_instruction_eip = vmcs12->exit_io_instruction_eip;
+ * evmcs->host_ia32_s_cet = vmcs12->host_ia32_s_cet;
+ * evmcs->host_ssp = vmcs12->host_ssp;
+ * evmcs->host_ia32_int_ssp_table_addr = vmcs12->host_ia32_int_ssp_table_addr;
+ * evmcs->guest_ia32_s_cet = vmcs12->guest_ia32_s_cet;
+ * evmcs->guest_ia32_lbr_ctl = vmcs12->guest_ia32_lbr_ctl;
+ * evmcs->guest_ia32_int_ssp_table_addr = vmcs12->guest_ia32_int_ssp_table_addr;
+ * evmcs->guest_ssp = vmcs12->guest_ssp;
*/

evmcs->guest_es_selector = vmcs12->guest_es_selector;
--
2.35.3


--=-=-=--