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KVM: TDX: Implement TDX vcpu enter/exit path

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Implement callbacks to enter/exit a TDX VCPU by calling tdh_vp_enter().
Ensure the TDX VCPU is in a correct state to run.

Do not pass arguments from/to vcpu->arch.regs[] unconditionally. Instead,
marshall state to/from the appropriate x86 registers only when needed,
i.e., to handle some TDVMCALL sub-leaves following KVM's ABI to leverage
the existing code.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Message-ID: <20250129095902.16391-6-adrian.hunter@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Isaku Yamahata 2025-01-29 11:58:54 +02:00 committed by Paolo Bonzini
parent 7172c753c2
commit 81bf912b2c
4 changed files with 90 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

20
arch/x86/kvm/vmx/main.c
View file

@ -145,6 +145,22 @@ static void vt_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)
vmx_update_cpu_dirty_logging(vcpu);
}
static int vt_vcpu_pre_run(struct kvm_vcpu *vcpu)
{
if (is_td_vcpu(vcpu))
return tdx_vcpu_pre_run(vcpu);
return vmx_vcpu_pre_run(vcpu);
}
static fastpath_t vt_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)
{
if (is_td_vcpu(vcpu))
return tdx_vcpu_run(vcpu, force_immediate_exit);
return vmx_vcpu_run(vcpu, force_immediate_exit);
}
static void vt_flush_tlb_all(struct kvm_vcpu *vcpu)
{
if (is_td_vcpu(vcpu)) {
@ -285,8 +301,8 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
.flush_tlb_gva = vt_flush_tlb_gva,
.flush_tlb_guest = vt_flush_tlb_guest,
.vcpu_pre_run = vmx_vcpu_pre_run,
.vcpu_run = vmx_vcpu_run,
.vcpu_pre_run = vt_vcpu_pre_run,
.vcpu_run = vt_vcpu_run,
.handle_exit = vmx_handle_exit,
.skip_emulated_instruction = vmx_skip_emulated_instruction,
.update_emulated_instruction = vmx_update_emulated_instruction,

62
arch/x86/kvm/vmx/tdx.c
View file

@ -12,6 +12,8 @@
#include "vmx.h"
#include "mmu/spte.h"
#include "common.h"
#include <trace/events/kvm.h>
#include "trace.h"
#pragma GCC poison to_vmx
@ -660,6 +662,66 @@ void tdx_vcpu_free(struct kvm_vcpu *vcpu)
tdx->state = VCPU_TD_STATE_UNINITIALIZED;
}
int tdx_vcpu_pre_run(struct kvm_vcpu *vcpu)
{
if (unlikely(to_tdx(vcpu)->state != VCPU_TD_STATE_INITIALIZED ||
to_kvm_tdx(vcpu->kvm)->state != TD_STATE_RUNNABLE))
return -EINVAL;
return 1;
}
static noinstr void tdx_vcpu_enter_exit(struct kvm_vcpu *vcpu)
{
struct vcpu_tdx *tdx = to_tdx(vcpu);
guest_state_enter_irqoff();
tdx->vp_enter_ret = tdh_vp_enter(&tdx->vp, &tdx->vp_enter_args);
guest_state_exit_irqoff();
}
#define TDX_REGS_AVAIL_SET (BIT_ULL(VCPU_EXREG_EXIT_INFO_1) | \
BIT_ULL(VCPU_EXREG_EXIT_INFO_2) | \
BIT_ULL(VCPU_REGS_RAX) | \
BIT_ULL(VCPU_REGS_RBX) | \
BIT_ULL(VCPU_REGS_RCX) | \
BIT_ULL(VCPU_REGS_RDX) | \
BIT_ULL(VCPU_REGS_RBP) | \
BIT_ULL(VCPU_REGS_RSI) | \
BIT_ULL(VCPU_REGS_RDI) | \
BIT_ULL(VCPU_REGS_R8) | \
BIT_ULL(VCPU_REGS_R9) | \
BIT_ULL(VCPU_REGS_R10) | \
BIT_ULL(VCPU_REGS_R11) | \
BIT_ULL(VCPU_REGS_R12) | \
BIT_ULL(VCPU_REGS_R13) | \
BIT_ULL(VCPU_REGS_R14) | \
BIT_ULL(VCPU_REGS_R15))
fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)
{
/*
* force_immediate_exit requires vCPU entering for events injection with
* an immediately exit followed. But The TDX module doesn't guarantee
* entry, it's already possible for KVM to _think_ it completely entry
* to the guest without actually having done so.
* Since KVM never needs to force an immediate exit for TDX, and can't
* do direct injection, just warn on force_immediate_exit.
*/
WARN_ON_ONCE(force_immediate_exit);
trace_kvm_entry(vcpu, force_immediate_exit);
tdx_vcpu_enter_exit(vcpu);
vcpu->arch.regs_avail &= TDX_REGS_AVAIL_SET;
trace_kvm_exit(vcpu, KVM_ISA_VMX);
return EXIT_FASTPATH_NONE;
}
void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa, int pgd_level)
{

3
arch/x86/kvm/vmx/tdx.h
View file

@ -48,11 +48,14 @@ enum vcpu_tdx_state {
struct vcpu_tdx {
struct kvm_vcpu vcpu;
struct vcpu_vt vt;
struct tdx_module_args vp_enter_args;
struct tdx_vp vp;
struct list_head cpu_list;
u64 vp_enter_ret;
enum vcpu_tdx_state state;
};

7
arch/x86/kvm/vmx/x86_ops.h
View file

@ -131,6 +131,8 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
int tdx_vcpu_create(struct kvm_vcpu *vcpu);
void tdx_vcpu_free(struct kvm_vcpu *vcpu);
void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
int tdx_vcpu_pre_run(struct kvm_vcpu *vcpu);
fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit);
int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
@ -157,6 +159,11 @@ static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOP
static inline int tdx_vcpu_create(struct kvm_vcpu *vcpu) { return -EOPNOTSUPP; }
static inline void tdx_vcpu_free(struct kvm_vcpu *vcpu) {}
static inline void tdx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) {}
static inline int tdx_vcpu_pre_run(struct kvm_vcpu *vcpu) { return -EOPNOTSUPP; }
static inline fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)
{
return EXIT_FASTPATH_NONE;
}
static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp) { return -EOPNOTSUPP; }