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linux-next/arch/x86/kvm/kvm_cache_regs.h
Liran Alon e40ff1d660 KVM: nVMX: Do not load EOI-exitmap while running L2
When L1 IOAPIC redirection-table is written, a request of
KVM_REQ_SCAN_IOAPIC is set on all vCPUs. This is done such that
all vCPUs will now recalc their IOAPIC handled vectors and load
it to their EOI-exitmap.

However, it could be that one of the vCPUs is currently running
L2. In this case, load_eoi_exitmap() will be called which would
write to vmcs02->eoi_exit_bitmap, which is wrong because
vmcs02->eoi_exit_bitmap should always be equal to
vmcs12->eoi_exit_bitmap. Furthermore, at this point
KVM_REQ_SCAN_IOAPIC was already consumed and therefore we will
never update vmcs01->eoi_exit_bitmap. This could lead to remote_irr
of some IOAPIC level-triggered entry to remain set forever.

Fix this issue by delaying the load of EOI-exitmap to when vCPU
is running L1.

One may wonder why not just delay entire KVM_REQ_SCAN_IOAPIC
processing to when vCPU is running L1. This is done in order to handle
correctly the case where LAPIC & IO-APIC of L1 is pass-throughed into
L2. In this case, vmcs12->virtual_interrupt_delivery should be 0. In
current nVMX implementation, that results in
vmcs02->virtual_interrupt_delivery to also be 0. Thus,
vmcs02->eoi_exit_bitmap is not used. Therefore, every L2 EOI cause
a #VMExit into L0 (either on MSR_WRITE to x2APIC MSR or
APIC_ACCESS/APIC_WRITE/EPT_MISCONFIG to APIC MMIO page).
In order for such L2 EOI to be broadcasted, if needed, from LAPIC
to IO-APIC, vcpu->arch.ioapic_handled_vectors must be updated
while L2 is running. Therefore, patch makes sure to delay only the
loading of EOI-exitmap but not the update of
vcpu->arch.ioapic_handled_vectors.

Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-03-21 14:16:44 +01:00

114 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef ASM_KVM_CACHE_REGS_H
#define ASM_KVM_CACHE_REGS_H
#define KVM_POSSIBLE_CR0_GUEST_BITS X86_CR0_TS
#define KVM_POSSIBLE_CR4_GUEST_BITS \
(X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR \
| X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_PGE)
static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu,
enum kvm_reg reg)
{
if (!test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail))
kvm_x86_ops->cache_reg(vcpu, reg);
return vcpu->arch.regs[reg];
}
static inline void kvm_register_write(struct kvm_vcpu *vcpu,
enum kvm_reg reg,
unsigned long val)
{
vcpu->arch.regs[reg] = val;
__set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
}
static inline unsigned long kvm_rip_read(struct kvm_vcpu *vcpu)
{
return kvm_register_read(vcpu, VCPU_REGS_RIP);
}
static inline void kvm_rip_write(struct kvm_vcpu *vcpu, unsigned long val)
{
kvm_register_write(vcpu, VCPU_REGS_RIP, val);
}
static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
{
might_sleep(); /* on svm */
if (!test_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_avail))
kvm_x86_ops->cache_reg(vcpu, (enum kvm_reg)VCPU_EXREG_PDPTR);
return vcpu->arch.walk_mmu->pdptrs[index];
}
static inline ulong kvm_read_cr0_bits(struct kvm_vcpu *vcpu, ulong mask)
{
ulong tmask = mask & KVM_POSSIBLE_CR0_GUEST_BITS;
if (tmask & vcpu->arch.cr0_guest_owned_bits)
kvm_x86_ops->decache_cr0_guest_bits(vcpu);
return vcpu->arch.cr0 & mask;
}
static inline ulong kvm_read_cr0(struct kvm_vcpu *vcpu)
{
return kvm_read_cr0_bits(vcpu, ~0UL);
}
static inline ulong kvm_read_cr4_bits(struct kvm_vcpu *vcpu, ulong mask)
{
ulong tmask = mask & KVM_POSSIBLE_CR4_GUEST_BITS;
if (tmask & vcpu->arch.cr4_guest_owned_bits)
kvm_x86_ops->decache_cr4_guest_bits(vcpu);
return vcpu->arch.cr4 & mask;
}
static inline ulong kvm_read_cr3(struct kvm_vcpu *vcpu)
{
if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail))
kvm_x86_ops->decache_cr3(vcpu);
return vcpu->arch.cr3;
}
static inline ulong kvm_read_cr4(struct kvm_vcpu *vcpu)
{
return kvm_read_cr4_bits(vcpu, ~0UL);
}
static inline u64 kvm_read_edx_eax(struct kvm_vcpu *vcpu)
{
return (kvm_register_read(vcpu, VCPU_REGS_RAX) & -1u)
| ((u64)(kvm_register_read(vcpu, VCPU_REGS_RDX) & -1u) << 32);
}
static inline void enter_guest_mode(struct kvm_vcpu *vcpu)
{
vcpu->arch.hflags |= HF_GUEST_MASK;
}
static inline void leave_guest_mode(struct kvm_vcpu *vcpu)
{
vcpu->arch.hflags &= ~HF_GUEST_MASK;
if (vcpu->arch.load_eoi_exitmap_pending) {
vcpu->arch.load_eoi_exitmap_pending = false;
kvm_make_request(KVM_REQ_LOAD_EOI_EXITMAP, vcpu);
}
}
static inline bool is_guest_mode(struct kvm_vcpu *vcpu)
{
return vcpu->arch.hflags & HF_GUEST_MASK;
}
static inline bool is_smm(struct kvm_vcpu *vcpu)
{
return vcpu->arch.hflags & HF_SMM_MASK;
}
#endif