KVM/arm64 fixes for 7.2, take #1

- Fix an accounting buglet when reclaiming pages from a protected
   guest
 
 - Fix a bunch of architectural compliance issues when injecting a
   synthesised exception, most of which were missing the PSTATE.IL bit
   indicating a 32bit-wide instruction
 
 - Another set of fixes addressing issues with translation of VNCR_EL2,
   including corner cases where the guest point that register at a RO
   page...
 
 - Don't warn when trapping accesses to ZCR_EL2 from an L2 guest, as
   that's not unexpected at all
 
 - Address a bunch of races with LPI migration vs LPIs being disabled
 
 - Fix a total howler of a bug combining FEAT_MOPS and NV, resulting in
   exception returning in the wrong place...
 
 - Coerce Fuad Tabba into a reviewer role, and may his Inbox catch
   fire!
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Merge tag 'kvmarm-fixes-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 7.2, take #1

- Fix an accounting buglet when reclaiming pages from a protected
  guest

- Fix a bunch of architectural compliance issues when injecting a
  synthesised exception, most of which were missing the PSTATE.IL bit
  indicating a 32bit-wide instruction

- Another set of fixes addressing issues with translation of VNCR_EL2,
  including corner cases where the guest point that register at a RO
  page...

- Don't warn when trapping accesses to ZCR_EL2 from an L2 guest, as
  that's not unexpected at all

- Address a bunch of races with LPI migration vs LPIs being disabled

- Fix a total howler of a bug combining FEAT_MOPS and NV, resulting in
  exception returning in the wrong place...

- Coerce Fuad Tabba into a reviewer role, and may his Inbox catch
  fire!
This commit is contained in:
Paolo Bonzini 2026-07-15 12:12:37 +02:00
commit 5b0d0464f6
11 changed files with 151 additions and 128 deletions

View File

@ -14191,6 +14191,7 @@ F: virt/kvm/*
KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)
M: Marc Zyngier <maz@kernel.org>
M: Oliver Upton <oupton@kernel.org>
R: Fuad Tabba <tabba@google.com>
R: Joey Gouly <joey.gouly@arm.com>
R: Steffen Eiden <seiden@linux.ibm.com>
R: Suzuki K Poulose <suzuki.poulose@arm.com>

View File

@ -388,6 +388,14 @@ struct s1_walk_result {
bool failed;
};
static inline void fail_s1_walk(struct s1_walk_result *wr, u8 fst, bool s1ptw)
{
wr->fst = fst;
wr->ptw = s1ptw;
wr->s2 = s1ptw;
wr->failed = true;
}
int __kvm_translate_va(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
struct s1_walk_result *wr, u64 va);
int __kvm_find_s1_desc_level(struct kvm_vcpu *vcpu, u64 va, u64 ipa,

View File

@ -11,14 +11,6 @@
#include <asm/kvm_mmu.h>
#include <asm/lsui.h>
static void fail_s1_walk(struct s1_walk_result *wr, u8 fst, bool s1ptw)
{
wr->fst = fst;
wr->ptw = s1ptw;
wr->s2 = s1ptw;
wr->failed = true;
}
#define S1_MMU_DISABLED (-127)
static int get_ia_size(struct s1_walk_info *wi)

View File

@ -2746,17 +2746,33 @@ static u64 kvm_check_illegal_exception_return(struct kvm_vcpu *vcpu, u64 spsr)
(spsr & PSR_MODE32_BIT) ||
(vcpu_el2_tge_is_set(vcpu) && (mode == PSR_MODE_EL1t ||
mode == PSR_MODE_EL1h))) {
/*
* The guest is playing with our nerves. Preserve EL, SP,
* masks, flags from the existing PSTATE, and set IL.
* The HW will then generate an Illegal State Exception
* immediately after ERET.
*/
spsr = *vcpu_cpsr(vcpu);
u64 mask;
spsr &= (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT |
PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT |
PSR_MODE_MASK | PSR_MODE32_BIT);
/*
* On an illegal exception return, the flags and masks are
* taken from the SPSR while PSTATE.{EL,SP,nRW} and, if
* FEAT_GCS, PSTATE.EXLOCK are unchanged (R_VWJHB). Set IL
* so the HW generates an Illegal State Exception right
* after ERET.
*/
mask = PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT |
PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT;
if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR1_EL1, PAN, IMP))
mask |= PSR_PAN_BIT;
if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, NMI, IMP))
mask |= ALLINT_ALLINT;
/* FEAT_SPE_EXC and FEAT_TRBE_EXC also gate PSTATE.PM one day... */
if (kvm_has_feat(vcpu->kvm, ID_AA64DFR1_EL1, EBEP, IMP))
mask |= BIT_ULL(32); /* SPSR_ELx.PM */
spsr &= mask;
mask = PSR_MODE_MASK | PSR_MODE32_BIT;
if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, GCS, IMP))
mask |= BIT_ULL(34); /* PSTATE.EXLOCK */
spsr |= *vcpu_cpsr(vcpu) & mask;
spsr |= PSR_IL_BIT;
}
@ -2784,7 +2800,7 @@ void kvm_emulate_nested_eret(struct kvm_vcpu *vcpu)
* ERET handling, and the guest will have a little surprise.
*/
if (kvm_has_pauth(vcpu->kvm, FPACCOMBINE) && !(spsr & PSR_IL_BIT)) {
esr &= ESR_ELx_ERET_ISS_ERETA;
esr &= (ESR_ELx_ERET_ISS_ERETA | ESR_ELx_IL);
esr |= FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_FPAC);
kvm_inject_nested_sync(vcpu, esr);
return;
@ -2826,6 +2842,7 @@ static void kvm_inject_el2_exception(struct kvm_vcpu *vcpu, u64 esr_el2,
break;
case except_type_serror:
kvm_pend_exception(vcpu, EXCEPT_AA64_EL2_SERR);
vcpu_write_sys_reg(vcpu, esr_el2, ESR_EL2);
break;
default:
WARN_ONCE(1, "Unsupported EL2 exception injection %d\n", type);
@ -2950,6 +2967,6 @@ int kvm_inject_nested_serror(struct kvm_vcpu *vcpu, u64 esr)
* vSError injection. Manually populate EC for an emulated SError
* exception.
*/
esr |= FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SERROR);
esr |= FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SERROR) | ESR_ELx_IL;
return kvm_inject_nested(vcpu, esr, except_type_serror);
}

View File

@ -448,16 +448,19 @@ static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
static inline bool kvm_hyp_handle_mops(struct kvm_vcpu *vcpu, u64 *exit_code)
{
u64 spsr;
*vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
arm64_mops_reset_regs(vcpu_gp_regs(vcpu), vcpu->arch.fault.esr_el2);
write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
/*
* Finish potential single step before executing the prologue
* instruction.
* instruction. Modify the hardware SPSR_EL2 directly, as vcpu_cpsr()
* may hold a synthetic (vEL2) value for a guest hypervisor.
*/
*vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS;
write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR);
spsr = read_sysreg_el2(SYS_SPSR);
write_sysreg_el2(spsr & ~DBG_SPSR_SS, SYS_SPSR);
return true;
}
@ -602,8 +605,6 @@ static inline bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
return false;
break;
case ESR_ELx_EC_SYS64:
if (WARN_ON_ONCE(!is_hyp_ctxt(vcpu)))
return false;
fallthrough;
case ESR_ELx_EC_SVE:
if (!sve_guest)

View File

@ -1056,7 +1056,8 @@ static u64 __pkvm_memshare_page_req(struct kvm_vcpu *vcpu, u64 ipa)
/* Fake up a data abort (level 3 translation fault on write) */
vcpu->arch.fault.esr_el2 = (ESR_ELx_EC_DABT_LOW << ESR_ELx_EC_SHIFT) |
ESR_ELx_WNR | ESR_ELx_FSC_FAULT |
ESR_ELx_IL | ESR_ELx_WNR |
ESR_ELx_FSC_FAULT |
FIELD_PREP(ESR_ELx_FSC_LEVEL, 3);
/* Shuffle the IPA around into the HPFAR */

View File

@ -268,6 +268,7 @@ static void inject_sync64(struct kvm_vcpu *vcpu, u64 esr)
write_sysreg_el1(esr, SYS_ESR);
write_sysreg_el1(read_sysreg_el2(SYS_ELR), SYS_ELR);
write_sysreg_el1(read_sysreg_el2(SYS_SPSR), SYS_SPSR);
write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR);
}
@ -278,7 +279,7 @@ static void inject_sync64(struct kvm_vcpu *vcpu, u64 esr)
*/
static void inject_undef64(struct kvm_vcpu *vcpu)
{
inject_sync64(vcpu, (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT));
inject_sync64(vcpu, (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT) | ESR_ELx_IL);
}
static u64 read_id_reg(const struct kvm_vcpu *vcpu,

View File

@ -138,11 +138,10 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
pend_sync_exception(vcpu);
/*
* Build an {i,d}abort, depending on the level and the
* instruction set. Report an external synchronous abort.
* Build an {i,d}abort, depending on the level.
* Report an external synchronous abort.
*/
if (kvm_vcpu_trap_il_is32bit(vcpu))
esr |= ESR_ELx_IL;
esr |= ESR_ELx_IL;
/*
* Here, the guest runs in AArch64 mode when in EL1. If we get
@ -170,14 +169,7 @@ void kvm_inject_sync(struct kvm_vcpu *vcpu, u64 esr)
static void inject_undef64(struct kvm_vcpu *vcpu)
{
u64 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
/*
* Build an unknown exception, depending on the instruction
* set.
*/
if (kvm_vcpu_trap_il_is32bit(vcpu))
esr |= ESR_ELx_IL;
u64 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT) | ESR_ELx_IL;
kvm_inject_sync(vcpu, esr);
}
@ -389,7 +381,7 @@ int kvm_inject_serror_esr(struct kvm_vcpu *vcpu, u64 esr)
*/
if (!serror_is_masked(vcpu)) {
pend_serror_exception(vcpu);
esr |= FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SERROR);
esr |= FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SERROR) | ESR_ELx_IL;
vcpu_write_sys_reg(vcpu, esr, exception_esr_elx(vcpu));
return 1;
}

View File

@ -24,6 +24,7 @@ struct vncr_tlb {
struct s1_walk_result wr;
u64 hpa;
bool hpa_writable;
/* -1 when not mapped on a CPU */
int cpu;
@ -1401,15 +1402,19 @@ static int kvm_translate_vncr(struct kvm_vcpu *vcpu, bool *is_gmem)
gfn = vt->wr.pa >> PAGE_SHIFT;
memslot = gfn_to_memslot(vcpu->kvm, gfn);
if (!memslot)
if (!memslot) {
fail_s1_walk(&vt->wr, ESR_ELx_FSC_EXTABT, false);
return -EFAULT;
}
*is_gmem = kvm_slot_has_gmem(memslot);
if (!*is_gmem) {
pfn = __kvm_faultin_pfn(memslot, gfn, write_fault ? FOLL_WRITE : 0,
&writable, &page);
if (is_error_noslot_pfn(pfn) || (write_fault && !writable))
if (is_error_noslot_pfn(pfn)) {
fail_s1_walk(&vt->wr, ESR_ELx_FSC_EXTABT, false);
return -EFAULT;
}
} else {
ret = kvm_gmem_get_pfn(vcpu->kvm, memslot, gfn, &pfn, &page, NULL);
if (ret) {
@ -1417,6 +1422,19 @@ static int kvm_translate_vncr(struct kvm_vcpu *vcpu, bool *is_gmem)
write_fault, false, false);
return ret;
}
writable = !(memslot->flags & KVM_MEM_READONLY);
}
/*
* FIXME: This check is too restrictive as KVM allows cacheable memory
* attributes for PFNMAP VMAs that have cacheable attributes in host
* stage-1.
*/
if (!pfn_is_map_memory(pfn)) {
kvm_release_faultin_page(vcpu->kvm, page, true, false);
fail_s1_walk(&vt->wr, ESR_ELx_FSC_EXTABT, false);
return -EINVAL;
}
scoped_guard(write_lock, &vcpu->kvm->mmu_lock) {
@ -1427,116 +1445,100 @@ static int kvm_translate_vncr(struct kvm_vcpu *vcpu, bool *is_gmem)
vt->gva = va;
vt->hpa = pfn << PAGE_SHIFT;
vt->hpa_writable = writable;
vt->valid = true;
vt->cpu = -1;
kvm_make_request(KVM_REQ_MAP_L1_VNCR_EL2, vcpu);
kvm_release_faultin_page(vcpu->kvm, page, false, vt->wr.pw);
kvm_release_faultin_page(vcpu->kvm, page, false, vt->wr.pw && vt->hpa_writable);
}
if (vt->wr.pw)
if (vt->wr.pw && vt->hpa_writable)
mark_page_dirty(vcpu->kvm, gfn);
return 0;
}
static void inject_vncr_perm(struct kvm_vcpu *vcpu)
static void handle_vncr_perm(struct kvm_vcpu *vcpu)
{
struct vncr_tlb *vt = vcpu->arch.vncr_tlb;
u64 esr = kvm_vcpu_get_esr(vcpu);
u64 fsc;
/*
* Promote to an external abort if the stage-1 permits writes but the
* HPA is read-only (e.g. RO memslot).
*/
if (kvm_is_write_fault(vcpu) && vt->wr.pw && !vt->hpa_writable)
fsc = ESR_ELx_FSC_EXTABT;
/*
* Otherwise, inject a permission fault using the guest's translation
* level rather than the host's.
*/
else
fsc = ESR_ELx_FSC_PERM_L(vt->wr.level);
/* Adjust the fault level to reflect that of the guest's */
esr &= ~ESR_ELx_FSC;
esr |= FIELD_PREP(ESR_ELx_FSC,
ESR_ELx_FSC_PERM_L(vt->wr.level));
esr |= FIELD_PREP(ESR_ELx_FSC, fsc);
kvm_inject_nested_sync(vcpu, esr);
}
static bool kvm_vncr_tlb_lookup(struct kvm_vcpu *vcpu)
{
struct vncr_tlb *vt = vcpu->arch.vncr_tlb;
lockdep_assert_held_read(&vcpu->kvm->mmu_lock);
if (!vt->valid)
return false;
if (read_vncr_el2(vcpu) != vt->gva)
return false;
if (vt->wr.nG)
return get_asid_by_regime(vcpu, TR_EL20) == vt->wr.asid;
return true;
}
int kvm_handle_vncr_abort(struct kvm_vcpu *vcpu)
{
struct vncr_tlb *vt = vcpu->arch.vncr_tlb;
u64 esr = kvm_vcpu_get_esr(vcpu);
bool is_gmem = false;
bool perm;
int ret;
WARN_ON_ONCE(!(esr & ESR_ELx_VNCR));
if (kvm_vcpu_abt_issea(vcpu))
return kvm_handle_guest_sea(vcpu);
if (esr_fsc_is_permission_fault(esr)) {
inject_vncr_perm(vcpu);
} else if (esr_fsc_is_translation_fault(esr)) {
bool valid, is_gmem = false;
int ret;
if (!esr_fsc_is_translation_fault(esr) && !esr_fsc_is_permission_fault(esr)) {
KVM_BUG(1, vcpu->kvm, "Unhandled VNCR abort, ESR=%llx\n", esr);
return -EIO;
}
scoped_guard(read_lock, &vcpu->kvm->mmu_lock)
valid = kvm_vncr_tlb_lookup(vcpu);
ret = kvm_translate_vncr(vcpu, &is_gmem);
switch (ret) {
case -EAGAIN:
/* Let's try again... */
return 1;
case -ENOMEM:
/*
* For guest_memfd, this indicates that it failed to
* create a folio to back the memory. Inform userspace.
*/
if (is_gmem)
return 0;
/* Otherwise, let's try again... */
break;
case -EFAULT:
case -EIO:
case -EHWPOISON:
if (is_gmem)
return 0;
fallthrough;
case -EINVAL:
case -ENOENT:
case -EACCES:
/*
* Translation failed, inject the corresponding
* exception back to EL2.
*/
esr &= ~ESR_ELx_FSC;
esr |= FIELD_PREP(ESR_ELx_FSC, vt->wr.fst);
if (!valid)
ret = kvm_translate_vncr(vcpu, &is_gmem);
else
ret = -EPERM;
switch (ret) {
case -EAGAIN:
/* Let's try again... */
break;
case -ENOMEM:
/*
* For guest_memfd, this indicates that it failed to
* create a folio to back the memory. Inform userspace.
*/
if (is_gmem)
return 0;
/* Otherwise, let's try again... */
break;
case -EFAULT:
case -EIO:
case -EHWPOISON:
if (is_gmem)
return 0;
fallthrough;
case -EINVAL:
case -ENOENT:
case -EACCES:
/*
* Translation failed, inject the corresponding
* exception back to EL2.
*/
BUG_ON(!vt->wr.failed);
esr &= ~ESR_ELx_FSC;
esr |= FIELD_PREP(ESR_ELx_FSC, vt->wr.fst);
kvm_inject_nested_sync(vcpu, esr);
break;
case -EPERM:
/* Hack to deal with POE until we get kernel support */
inject_vncr_perm(vcpu);
break;
case 0:
break;
}
} else {
WARN_ONCE(1, "Unhandled VNCR abort, ESR=%llx\n", esr);
kvm_inject_nested_sync(vcpu, esr);
break;
case 0:
perm = kvm_is_write_fault(vcpu) ? vt->wr.pw && vt->hpa_writable : vt->wr.pr;
if (!perm)
handle_vncr_perm(vcpu);
break;
}
return 1;
@ -1574,7 +1576,7 @@ static void kvm_map_l1_vncr(struct kvm_vcpu *vcpu)
vt->cpu = smp_processor_id();
if (vt->wr.pw && vt->wr.pr)
if (vt->hpa_writable && vt->wr.pw && vt->wr.pr)
prot = PAGE_KERNEL;
else if (vt->wr.pr)
prot = PAGE_KERNEL_RO;

View File

@ -352,7 +352,7 @@ static int __pkvm_pgtable_stage2_reclaim(struct kvm_pgtable *pgt, u64 start, u64
page = pfn_to_page(mapping->pfn);
WARN_ON_ONCE(mapping->nr_pages != 1);
unpin_user_pages_dirty_lock(&page, 1, true);
account_locked_vm(current->mm, 1, false);
account_locked_vm(kvm->mm, 1, false);
pkvm_mapping_remove(mapping, &pgt->pkvm_mappings);
kfree(mapping);
}

View File

@ -203,6 +203,7 @@ void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu)
list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
if (irq_is_lpi(vcpu->kvm, irq->intid)) {
raw_spin_lock(&irq->irq_lock);
irq->pending_latch = false;
list_del(&irq->ap_list);
irq->vcpu = NULL;
raw_spin_unlock(&irq->irq_lock);
@ -792,7 +793,11 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
continue;
}
/* This interrupt looks like it has to be migrated. */
/*
* This interrupt looks like it has to be migrated,
* make sure it is kept alive while locks are dropped.
*/
vgic_get_irq_ref(irq);
raw_spin_unlock(&irq->irq_lock);
raw_spin_unlock(&vgic_cpu->ap_list_lock);
@ -815,15 +820,16 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
raw_spin_lock(&irq->irq_lock);
/*
* If the affinity has been preserved, move the
* interrupt around. Otherwise, it means things have
* changed while the interrupt was unlocked, and we
* need to replay this.
* If the interrupt is still ours and its affinity has
* been preserved, move it around. Otherwise, it means
* things have changed while the interrupt was unlocked
* (it may even have been taken off the list with its
* affinity left untouched), and we need to replay this.
*
* In all cases, we cannot trust the list not to have
* changed, so we restart from the beginning.
*/
if (target_vcpu == vgic_target_oracle(irq)) {
if (irq->vcpu == vcpu && target_vcpu == vgic_target_oracle(irq)) {
struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu;
list_del(&irq->ap_list);
@ -836,6 +842,8 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
raw_spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
raw_spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);
deleted_lpis |= vgic_put_irq_norelease(vcpu->kvm, irq);
if (target_vcpu_needs_kick) {
kvm_make_request(KVM_REQ_IRQ_PENDING, target_vcpu);
kvm_vcpu_kick(target_vcpu);