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Merge tag 'kvm-x86-vmx-6.4' of https://github.com/kvm-x86/linux into …
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KVM VMX changes for 6.4:

 - Fix a bug in emulation of ENCLS in compatibility mode

 - Allow emulation of NOP and PAUSE for L2

 - Misc cleanups
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bonzini committed Apr 26, 2023
2 parents 4a5fd41 + 4984563 commit b3c9805
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Showing 3 changed files with 91 additions and 40 deletions.
112 changes: 74 additions & 38 deletions arch/x86/kvm/vmx/nested.c
Original file line number Diff line number Diff line change
Expand Up @@ -6756,36 +6756,9 @@ static u64 nested_vmx_calc_vmcs_enum_msr(void)
return (u64)max_idx << VMCS_FIELD_INDEX_SHIFT;
}

/*
* nested_vmx_setup_ctls_msrs() sets up variables containing the values to be
* returned for the various VMX controls MSRs when nested VMX is enabled.
* The same values should also be used to verify that vmcs12 control fields are
* valid during nested entry from L1 to L2.
* Each of these control msrs has a low and high 32-bit half: A low bit is on
* if the corresponding bit in the (32-bit) control field *must* be on, and a
* bit in the high half is on if the corresponding bit in the control field
* may be on. See also vmx_control_verify().
*/
void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
static void nested_vmx_setup_pinbased_ctls(struct vmcs_config *vmcs_conf,
struct nested_vmx_msrs *msrs)
{
struct nested_vmx_msrs *msrs = &vmcs_conf->nested;

/*
* Note that as a general rule, the high half of the MSRs (bits in
* the control fields which may be 1) should be initialized by the
* intersection of the underlying hardware's MSR (i.e., features which
* can be supported) and the list of features we want to expose -
* because they are known to be properly supported in our code.
* Also, usually, the low half of the MSRs (bits which must be 1) can
* be set to 0, meaning that L1 may turn off any of these bits. The
* reason is that if one of these bits is necessary, it will appear
* in vmcs01 and prepare_vmcs02, when it bitwise-or's the control
* fields of vmcs01 and vmcs02, will turn these bits off - and
* nested_vmx_l1_wants_exit() will not pass related exits to L1.
* These rules have exceptions below.
*/

/* pin-based controls */
msrs->pinbased_ctls_low =
PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR;

Expand All @@ -6798,8 +6771,11 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
msrs->pinbased_ctls_high |=
PIN_BASED_ALWAYSON_WITHOUT_TRUE_MSR |
PIN_BASED_VMX_PREEMPTION_TIMER;
}

/* exit controls */
static void nested_vmx_setup_exit_ctls(struct vmcs_config *vmcs_conf,
struct nested_vmx_msrs *msrs)
{
msrs->exit_ctls_low =
VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR;

Expand All @@ -6818,8 +6794,11 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)

/* We support free control of debug control saving. */
msrs->exit_ctls_low &= ~VM_EXIT_SAVE_DEBUG_CONTROLS;
}

/* entry controls */
static void nested_vmx_setup_entry_ctls(struct vmcs_config *vmcs_conf,
struct nested_vmx_msrs *msrs)
{
msrs->entry_ctls_low =
VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR;

Expand All @@ -6835,8 +6814,11 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)

/* We support free control of debug control loading. */
msrs->entry_ctls_low &= ~VM_ENTRY_LOAD_DEBUG_CONTROLS;
}

/* cpu-based controls */
static void nested_vmx_setup_cpubased_ctls(struct vmcs_config *vmcs_conf,
struct nested_vmx_msrs *msrs)
{
msrs->procbased_ctls_low =
CPU_BASED_ALWAYSON_WITHOUT_TRUE_MSR;

Expand Down Expand Up @@ -6868,12 +6850,12 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
/* We support free control of CR3 access interception. */
msrs->procbased_ctls_low &=
~(CPU_BASED_CR3_LOAD_EXITING | CPU_BASED_CR3_STORE_EXITING);
}

/*
* secondary cpu-based controls. Do not include those that
* depend on CPUID bits, they are added later by
* vmx_vcpu_after_set_cpuid.
*/
static void nested_vmx_setup_secondary_ctls(u32 ept_caps,
struct vmcs_config *vmcs_conf,
struct nested_vmx_msrs *msrs)
{
msrs->secondary_ctls_low = 0;

msrs->secondary_ctls_high = vmcs_conf->cpu_based_2nd_exec_ctrl;
Expand Down Expand Up @@ -6951,16 +6933,22 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)

if (enable_sgx)
msrs->secondary_ctls_high |= SECONDARY_EXEC_ENCLS_EXITING;
}

/* miscellaneous data */
static void nested_vmx_setup_misc_data(struct vmcs_config *vmcs_conf,
struct nested_vmx_msrs *msrs)
{
msrs->misc_low = (u32)vmcs_conf->misc & VMX_MISC_SAVE_EFER_LMA;
msrs->misc_low |=
MSR_IA32_VMX_MISC_VMWRITE_SHADOW_RO_FIELDS |
VMX_MISC_EMULATED_PREEMPTION_TIMER_RATE |
VMX_MISC_ACTIVITY_HLT |
VMX_MISC_ACTIVITY_WAIT_SIPI;
msrs->misc_high = 0;
}

static void nested_vmx_setup_basic(struct nested_vmx_msrs *msrs)
{
/*
* This MSR reports some information about VMX support. We
* should return information about the VMX we emulate for the
Expand All @@ -6975,7 +6963,10 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)

if (cpu_has_vmx_basic_inout())
msrs->basic |= VMX_BASIC_INOUT;
}

static void nested_vmx_setup_cr_fixed(struct nested_vmx_msrs *msrs)
{
/*
* These MSRs specify bits which the guest must keep fixed on
* while L1 is in VMXON mode (in L1's root mode, or running an L2).
Expand All @@ -6992,6 +6983,51 @@ void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)

if (vmx_umip_emulated())
msrs->cr4_fixed1 |= X86_CR4_UMIP;
}

/*
* nested_vmx_setup_ctls_msrs() sets up variables containing the values to be
* returned for the various VMX controls MSRs when nested VMX is enabled.
* The same values should also be used to verify that vmcs12 control fields are
* valid during nested entry from L1 to L2.
* Each of these control msrs has a low and high 32-bit half: A low bit is on
* if the corresponding bit in the (32-bit) control field *must* be on, and a
* bit in the high half is on if the corresponding bit in the control field
* may be on. See also vmx_control_verify().
*/
void nested_vmx_setup_ctls_msrs(struct vmcs_config *vmcs_conf, u32 ept_caps)
{
struct nested_vmx_msrs *msrs = &vmcs_conf->nested;

/*
* Note that as a general rule, the high half of the MSRs (bits in
* the control fields which may be 1) should be initialized by the
* intersection of the underlying hardware's MSR (i.e., features which
* can be supported) and the list of features we want to expose -
* because they are known to be properly supported in our code.
* Also, usually, the low half of the MSRs (bits which must be 1) can
* be set to 0, meaning that L1 may turn off any of these bits. The
* reason is that if one of these bits is necessary, it will appear
* in vmcs01 and prepare_vmcs02, when it bitwise-or's the control
* fields of vmcs01 and vmcs02, will turn these bits off - and
* nested_vmx_l1_wants_exit() will not pass related exits to L1.
* These rules have exceptions below.
*/
nested_vmx_setup_pinbased_ctls(vmcs_conf, msrs);

nested_vmx_setup_exit_ctls(vmcs_conf, msrs);

nested_vmx_setup_entry_ctls(vmcs_conf, msrs);

nested_vmx_setup_cpubased_ctls(vmcs_conf, msrs);

nested_vmx_setup_secondary_ctls(ept_caps, vmcs_conf, msrs);

nested_vmx_setup_misc_data(vmcs_conf, msrs);

nested_vmx_setup_basic(msrs);

nested_vmx_setup_cr_fixed(msrs);

msrs->vmcs_enum = nested_vmx_calc_vmcs_enum_msr();
}
Expand Down
4 changes: 2 additions & 2 deletions arch/x86/kvm/vmx/sgx.c
Original file line number Diff line number Diff line change
Expand Up @@ -29,14 +29,14 @@ static int sgx_get_encls_gva(struct kvm_vcpu *vcpu, unsigned long offset,

/* Skip vmcs.GUEST_DS retrieval for 64-bit mode to avoid VMREADs. */
*gva = offset;
if (!is_long_mode(vcpu)) {
if (!is_64_bit_mode(vcpu)) {
vmx_get_segment(vcpu, &s, VCPU_SREG_DS);
*gva += s.base;
}

if (!IS_ALIGNED(*gva, alignment)) {
fault = true;
} else if (likely(is_long_mode(vcpu))) {
} else if (likely(is_64_bit_mode(vcpu))) {
fault = is_noncanonical_address(*gva, vcpu);
} else {
*gva &= 0xffffffff;
Expand Down
15 changes: 15 additions & 0 deletions arch/x86/kvm/vmx/vmx.c
Original file line number Diff line number Diff line change
Expand Up @@ -7900,6 +7900,21 @@ static int vmx_check_intercept(struct kvm_vcpu *vcpu,
/* FIXME: produce nested vmexit and return X86EMUL_INTERCEPTED. */
break;

case x86_intercept_pause:
/*
* PAUSE is a single-byte NOP with a REPE prefix, i.e. collides
* with vanilla NOPs in the emulator. Apply the interception
* check only to actual PAUSE instructions. Don't check
* PAUSE-loop-exiting, software can't expect a given PAUSE to
* exit, i.e. KVM is within its rights to allow L2 to execute
* the PAUSE.
*/
if ((info->rep_prefix != REPE_PREFIX) ||
!nested_cpu_has2(vmcs12, CPU_BASED_PAUSE_EXITING))
return X86EMUL_CONTINUE;

break;

/* TODO: check more intercepts... */
default:
break;
Expand Down

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