Re: [PATCH 44/59] KVM: arm64: nv: Trap and emulate TLBI instructions from virtual EL2

[Julien Thierry <julien.thierry@arm.com>]

On 21/06/2019 10:38, Marc Zyngier wrote:
> From: Jintack Lim <jintack.lim@linaro.org>
> 
> When supporting nested virtualization a guest hypervisor executing TLBI
> instructions must be trapped and emulated by the host hypervisor,
> because the guest hypervisor can only affect physical TLB entries
> relating to its own execution environment (virtual EL2 in EL1) but not
> to the nested guests as required by the semantics of the instructions
> and TLBI instructions might also result in updates (invalidations) to
> shadow page tables.
> 
> This patch does several things.
> 
> 1. List and define all TLBI system instructions to emulate.
> 
> 2. Emulate TLBI ALLE2(IS) instruction executed in the virtual EL2. Since
> we emulate the virtual EL2 in the EL1, we invalidate EL1&0 regime stage
> 1 TLB entries with setting vttbr_el2 having the VMID of the virtual EL2.
> 
> 3. Emulate TLBI VAE2* instruction executed in the virtual EL2. Based on the
> same principle as TLBI ALLE2 instruction, we can simply emulate those
> instructions by executing corresponding VAE1* instructions with the
> virtual EL2's VMID assigned by the host hypervisor.
> 
> Note that we are able to emulate TLBI ALLE2IS precisely by only
> invalidating stage 1 TLB entries via TLBI VMALL1IS instruction, but to
> make it simeple, we reuse the existing function, __kvm_tlb_flush_vmid(),
> which invalidates both of stage 1 and 2 TLB entries.
> 
> 4. TLBI ALLE1(IS) instruction invalidates all EL1&0 regime stage 1 and 2
> TLB entries (on all PEs in the same Inner Shareable domain). To emulate
> these instructions, we first need to clear all the mappings in the
> shadow page tables since executing those instructions implies the change
> of mappings in the stage 2 page tables maintained by the guest
> hypervisor.  We then need to invalidate all EL1&0 regime stage 1 and 2
> TLB entries of all VMIDs, which are assigned by the host hypervisor, for
> this VM.
> 
> 5. Based on the same principle as TLBI ALLE1(IS) emulation, we clear the
> mappings in the shadow stage-2 page tables and invalidate TLB entries.
> But this time we do it only for the current VMID from the guest
> hypervisor's perspective, not for all VMIDs.
> 
> 6. Based on the same principle as TLBI ALLE1(IS) and TLBI VMALLS12E1(IS)
> emulation, we clear the mappings in the shadow stage-2 page tables and
> invalidate TLB entries. We do it only for one mapping for the current
> VMID from the guest hypervisor's view.
> 
> 7. Forward system instruction traps to the virtual EL2 if a
> corresponding bit in the virtual HCR_EL2 is set.
> 
> 8. Even though a guest hypervisor can execute TLBI instructions that are
> accesible at EL1 without trap, it's wrong; All those TLBI instructions
> work based on current VMID, and when running a guest hypervisor current
> VMID is the one for itself, not the one from the virtual vttbr_el2. So
> letting a guest hypervisor execute those TLBI instructions results in
> invalidating its own TLB entries and leaving invalid TLB entries
> unhandled.
> 
> Therefore we trap and emulate those TLBI instructions. The emulation is
> simple; we find a shadow VMID mapped to the virtual vttbr_el2, set it in
> the physical vttbr_el2, then execute the same instruction in EL2.
> 
> We don't set HCR_EL2.TTLB bit yet.
> 
>   [ Changes performed by Marc Zynger:
> 
>     The TLBI handling code more or less directly execute the same
>     instruction that has been trapped (with an EL2->EL1 conversion
>     in the case of an EL2 TLBI), but that's unfortunately not enough:
> 
>     - TLBIs must be upgraded to the Inner Shareable domain to account
>       for vcpu migration, just like we already have with HCR_EL2.FB.
> 
>     - The DSB instruction that synchronises these must thus be on
>       the Inner Shareable domain as well.
> 
>     - Prior to executing the TLBI, we need another DSB ISHST to make
>       sure that the update to the page tables is now visible.
> 
>       Ordering of system instructions fixed
> 
>     - The current TLB invalidation code is pretty buggy, as it assume a
>       page mapping. On the contrary, it is likely that TLB invalidation
>       will cover more than a single page, and the size should be decided
>       by the guests configuration (and not the host's).
> 
>       Since we don't cache the guest mapping sizes in the shadow PT yet,
>       let's assume the worse case (a block mapping) and invalidate that.
> 
>       Take this opportunity to fix the decoding of the parameter (it
>       isn't a straight IPA).
> 
>     - In general, we always emulate local TBL invalidations as being
>       as upgraded to the Inner Shareable domain so that we can easily
>       deal with vcpu migration. This is consistent with the fact that
>       we set HCR_EL2.FB when running non-nested VMs.
> 
>       So let's emulate TLBI ALLE2 as ALLE2IS.
>   ]
> 
>   [ Changes performed by Christoffer Dall:
> 
>     Sometimes when we are invalidating the TLB for a certain S2 MMU
>     context, this context can also have EL2 context associated with it
>     and we have to invalidate this too.
>   ]
> 
> Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
> ---
>  arch/arm64/include/asm/kvm_asm.h |   2 +
>  arch/arm64/include/asm/sysreg.h  |  36 ++++++
>  arch/arm64/kvm/hyp/tlb.c         |  81 +++++++++++++
>  arch/arm64/kvm/sys_regs.c        | 201 +++++++++++++++++++++++++++++++
>  virt/kvm/arm/mmu.c               |  18 ++-
>  5 files changed, 337 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index 1cfa4d2cf772..9cb9ab066ebc 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -67,6 +67,8 @@ extern void __kvm_flush_vm_context(void);
>  extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa);
>  extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
>  extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
> +extern void __kvm_tlb_vae2(struct kvm_s2_mmu *mmu, u64 va, u64 sys_encoding);
> +extern void __kvm_tlb_el1_instr(struct kvm_s2_mmu *mmu, u64 val, u64 sys_encoding);
>  
>  extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
>  extern void __kvm_at_s1e01(struct kvm_vcpu *vcpu, u32 op, u64 vaddr);
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index b3a8d21c07b3..e0912ececd92 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -553,6 +553,42 @@
>  #define OP_AT_S12E0R	sys_insn(AT_Op0, 4, AT_CRn, 8, 6)
>  #define OP_AT_S12E0W	sys_insn(AT_Op0, 4, AT_CRn, 8, 7)
>  
> +/* TLBI instructions */
> +#define TLBI_Op0	1
> +#define TLBI_Op1_EL1	0	/* Accessible from EL1 or higher */
> +#define TLBI_Op1_EL2	4	/* Accessible from EL2 or higher */
> +#define TLBI_CRn	8
> +#define tlbi_insn_el1(CRm, Op2)	sys_insn(TLBI_Op0, TLBI_Op1_EL1, TLBI_CRn, (CRm), (Op2))
> +#define tlbi_insn_el2(CRm, Op2)	sys_insn(TLBI_Op0, TLBI_Op1_EL2, TLBI_CRn, (CRm), (Op2))
> +
> +#define OP_TLBI_VMALLE1IS	tlbi_insn_el1(3, 0)
> +#define OP_TLBI_VAE1IS		tlbi_insn_el1(3, 1)
> +#define OP_TLBI_ASIDE1IS	tlbi_insn_el1(3, 2)
> +#define OP_TLBI_VAAE1IS		tlbi_insn_el1(3, 3)
> +#define OP_TLBI_VALE1IS		tlbi_insn_el1(3, 5)
> +#define OP_TLBI_VAALE1IS	tlbi_insn_el1(3, 7)
> +#define OP_TLBI_VMALLE1		tlbi_insn_el1(7, 0)
> +#define OP_TLBI_VAE1		tlbi_insn_el1(7, 1)
> +#define OP_TLBI_ASIDE1		tlbi_insn_el1(7, 2)
> +#define OP_TLBI_VAAE1		tlbi_insn_el1(7, 3)
> +#define OP_TLBI_VALE1		tlbi_insn_el1(7, 5)
> +#define OP_TLBI_VAALE1		tlbi_insn_el1(7, 7)
> +
> +#define OP_TLBI_IPAS2E1IS	tlbi_insn_el2(0, 1)
> +#define OP_TLBI_IPAS2LE1IS	tlbi_insn_el2(0, 5)
> +#define OP_TLBI_ALLE2IS		tlbi_insn_el2(3, 0)
> +#define OP_TLBI_VAE2IS		tlbi_insn_el2(3, 1)
> +#define OP_TLBI_ALLE1IS		tlbi_insn_el2(3, 4)
> +#define OP_TLBI_VALE2IS		tlbi_insn_el2(3, 5)
> +#define OP_TLBI_VMALLS12E1IS	tlbi_insn_el2(3, 6)
> +#define OP_TLBI_IPAS2E1		tlbi_insn_el2(4, 1)
> +#define OP_TLBI_IPAS2LE1	tlbi_insn_el2(4, 5)
> +#define OP_TLBI_ALLE2		tlbi_insn_el2(7, 0)
> +#define OP_TLBI_VAE2		tlbi_insn_el2(7, 1)
> +#define OP_TLBI_ALLE1		tlbi_insn_el2(7, 4)
> +#define OP_TLBI_VALE2		tlbi_insn_el2(7, 5)
> +#define OP_TLBI_VMALLS12E1	tlbi_insn_el2(7, 6)
> +
>  /* Common SCTLR_ELx flags. */
>  #define SCTLR_ELx_DSSBS	(_BITUL(44))
>  #define SCTLR_ELx_ENIA	(_BITUL(31))
> diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c
> index 779405db3fb3..026afbf1a697 100644
> --- a/arch/arm64/kvm/hyp/tlb.c
> +++ b/arch/arm64/kvm/hyp/tlb.c
> @@ -205,3 +205,84 @@ void __hyp_text __kvm_flush_vm_context(void)
>  	asm volatile("ic ialluis" : : );
>  	dsb(ish);
>  }
> +
> +void __hyp_text __kvm_tlb_vae2(struct kvm_s2_mmu *mmu, u64 va, u64 sys_encoding)
> +{
> +	struct tlb_inv_context cxt;
> +
> +	dsb(ishst);
> +
> +	/* Switch to requested VMID */
> +	__tlb_switch_to_guest()(mmu, &cxt);
> +
> +	/*
> +	 * Execute the EL1 version of TLBI VAE2* instruction, forcing
> +	 * an upgrade to the Inner Shareable domain in order to
> +	 * perform the invalidation on all CPUs.
> +	 */
> +	switch (sys_encoding) {
> +	case OP_TLBI_VAE2:
> +	case OP_TLBI_VAE2IS:
> +		__tlbi(vae1is, va);
> +		break;
> +	case OP_TLBI_VALE2:
> +	case OP_TLBI_VALE2IS:
> +		__tlbi(vale1is, va);
> +		break;
> +	default:
> +		break;
> +	}
> +	dsb(ish);
> +	isb();
> +
> +	__tlb_switch_to_host()(&cxt);
> +}
> +
> +void __hyp_text __kvm_tlb_el1_instr(struct kvm_s2_mmu *mmu, u64 val, u64 sys_encoding)
> +{
> +	struct tlb_inv_context cxt;
> +
> +	dsb(ishst);
> +
> +	/* Switch to requested VMID */
> +	__tlb_switch_to_guest()(mmu, &cxt);
> +
> +	/*
> +	 * Execute the same instruction as the guest hypervisor did,
> +	 * expanding the scope of local TLB invalidations to the Inner
> +	 * Shareable domain so that it takes place on all CPUs. This
> +	 * is equivalent to having HCR_EL2.FB set.
> +	 */
> +	switch (sys_encoding) {
> +	case OP_TLBI_VMALLE1:
> +	case OP_TLBI_VMALLE1IS:
> +		__tlbi(vmalle1is);
> +		break;
> +	case OP_TLBI_VAE1:
> +	case OP_TLBI_VAE1IS:
> +		__tlbi(vae1is, val);
> +		break;
> +	case OP_TLBI_ASIDE1:
> +	case OP_TLBI_ASIDE1IS:
> +		__tlbi(aside1is, val);
> +		break;
> +	case OP_TLBI_VAAE1:
> +	case OP_TLBI_VAAE1IS:
> +		__tlbi(vaae1is, val);
> +		break;
> +	case OP_TLBI_VALE1:
> +	case OP_TLBI_VALE1IS:
> +		__tlbi(vale1is, val);
> +		break;
> +	case OP_TLBI_VAALE1:
> +	case OP_TLBI_VAALE1IS:
> +		__tlbi(vaale1is, val);
> +		break;
> +	default:
> +		break;
> +	}
> +	dsb(ish);
> +	isb();
> +
> +	__tlb_switch_to_host()(&cxt);
> +}
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 102419b837e8..0343682fe47f 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1661,6 +1661,11 @@ static bool forward_at_traps(struct kvm_vcpu *vcpu)
>  	return forward_traps(vcpu, HCR_AT);
>  }
>  
> +static bool forward_ttlb_traps(struct kvm_vcpu *vcpu)
> +{
> +	return forward_traps(vcpu, HCR_TTLB);
> +}
> +
>  /* This function is to support the recursive nested virtualization */
>  static bool forward_nv1_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
>  {
> @@ -2251,6 +2256,174 @@ static bool handle_s12w(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
>  	return handle_s12(vcpu, p, r, true);
>  }
>  
> +static bool handle_alle2is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> +			   const struct sys_reg_desc *r)
> +{
> +	/*
> +	 * To emulate invalidating all EL2 regime stage 1 TLB entries for all
> +	 * PEs, executing TLBI VMALLE1IS is enough. But reuse the existing
> +	 * interface for the simplicity; invalidating stage 2 entries doesn't
> +	 * affect the correctness.
> +	 */
> +	kvm_call_hyp(__kvm_tlb_flush_vmid, &vcpu->kvm->arch.mmu);
> +	return true;
> +}
> +
> +static bool handle_vae2(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> +		       const struct sys_reg_desc *r)
> +{
> +	int sys_encoding = sys_insn(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2);
> +
> +	/*
> +	 * Based on the same principle as TLBI ALLE2 instruction emulation, we
> +	 * emulate TLBI VAE2* instructions by executing corresponding TLBI VAE1*
> +	 * instructions with the virtual EL2's VMID assigned by the host
> +	 * hypervisor.
> +	 */
> +	kvm_call_hyp(__kvm_tlb_vae2, &vcpu->kvm->arch.mmu,
> +		     p->regval, sys_encoding);
> +	return true;
> +}
> +
> +static bool handle_alle1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> +			   const struct sys_reg_desc *r)
> +{
> +	struct kvm_s2_mmu *mmu = &vcpu->kvm->arch.mmu;
> +	spin_lock(&vcpu->kvm->mmu_lock);
> +
> +	/*
> +	 * Clear all mappings in the shadow page tables and invalidate the stage
> +	 * 1 and 2 TLB entries via kvm_tlb_flush_vmid_ipa().
> +	 */
> +	kvm_nested_s2_clear(vcpu->kvm);
> +
> +	if (mmu->vmid.vmid_gen) {
> +		/*
> +		 * Invalidate the stage 1 and 2 TLB entries for the host OS
> +		 * in a VM only if there is one.
> +		 */
> +		kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
> +	}
> +
> +	spin_unlock(&vcpu->kvm->mmu_lock);
> +
> +	return true;
> +}
> +
> +static bool handle_vmalls12e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> +				const struct sys_reg_desc *r)
> +{
> +	u64 vttbr = vcpu_read_sys_reg(vcpu, VTTBR_EL2);
> +	struct kvm_s2_mmu *mmu;
> +
> +	spin_lock(&vcpu->kvm->mmu_lock);
> +
> +	mmu = lookup_s2_mmu(vcpu->kvm, vttbr, HCR_VM);
> +	if (mmu)
> +		kvm_unmap_stage2_range(mmu, 0, kvm_phys_size(vcpu->kvm));
> +
> +	mmu = lookup_s2_mmu(vcpu->kvm, vttbr, 0);
> +	if (mmu)
> +		kvm_unmap_stage2_range(mmu, 0, kvm_phys_size(vcpu->kvm));
> +
> +	spin_unlock(&vcpu->kvm->mmu_lock);
> +
> +	return true;
> +}
> +
> +static bool handle_ipas2e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> +			     const struct sys_reg_desc *r)
> +{
> +	u64 vttbr = vcpu_read_sys_reg(vcpu, VTTBR_EL2);
> +	u64 vtcr = vcpu_read_sys_reg(vcpu, VTCR_EL2);
> +	struct kvm_s2_mmu *mmu;
> +	u64 base_addr;
> +	int max_size;
> +
> +	/*
> +	 * We drop a number of things from the supplied value:
> +	 *
> +	 * - NS bit: we're non-secure only.
> +	 *
> +	 * - TTL field: We already have the granule size from the
> +	 *   VTCR_EL2.TG0 field, and the level is only relevant to the
> +	 *   guest's S2PT.
> +	 *
> +	 * - IPA[51:48]: We don't support 52bit IPA just yet...
> +	 *
> +	 * And of course, adjust the IPA to be on an actual address.
> +	 */
> +	base_addr = (p->regval & GENMASK_ULL(35, 0)) << 12;
> +
> +	/* Compute the maximum extent of the invalidation */
> +	switch ((vtcr & VTCR_EL2_TG0_MASK)) {
> +	case VTCR_EL2_TG0_4K:
> +		max_size = SZ_1G;
> +		break;
> +	case VTCR_EL2_TG0_16K:
> +		max_size = SZ_32M;
> +		break;
> +	case VTCR_EL2_TG0_64K:
> +		/*
> +		 * No, we do not support 52bit IPA in nested yet. Once
> +		 * we do, this should be 4TB.
> +		 */
> +		/* FIXME: remove the 52bit PA support from the IDregs */
> +		max_size = SZ_512M;
> +		break;
> +	default:
> +		BUG();
> +	}
> +
> +	spin_lock(&vcpu->kvm->mmu_lock);
> +
> +	mmu = lookup_s2_mmu(vcpu->kvm, vttbr, HCR_VM);
> +	if (mmu)
> +		kvm_unmap_stage2_range(mmu, base_addr, max_size);
> +
> +	mmu = lookup_s2_mmu(vcpu->kvm, vttbr, 0);
> +	if (mmu)
> +		kvm_unmap_stage2_range(mmu, base_addr, max_size);
> +
> +	spin_unlock(&vcpu->kvm->mmu_lock);

For lookup_s2_mmu(), sometimes we take kvm->lock, sometimes we take
kvm->mmu_lock instead (without the other being taken). The comment above
lookup_s2_mmu() suggest kvm->lock is the one that should be taken, but
I'm not sure which is the correct one.

Should the code here be something like the following?

	mutex_lock(&vcpu->kvm->lock);

	mmu = lookup_s2_mmu(vcpu->kvm, vttbr, HCR_VM);
	if (!mmu)
		mmu = lookup_s2_mmu(vcpu->kvm, vttbr, HCR_VM);

	if (mmu) {
		spin_lock(&vcpu->kvm->mmu_lock);
		kvm_unmap_stage2_range(...);
		spin_unlock(&vcpu->kvm_mmu_lock);
	}
	mutex_unlock(&vcpu->kvm->lock);


Overall, there seems to be other places where lookup_s2_mmu() is called
only with kvm->mmu_lock taken instead of kvm->lock. Should the comment
be fixed to kvm->mmu_lock and callers taking only kvm->lock (i.e.
creation/destruction of s2_mmu) be updated?


> +
> +	return true;
> +}
> +
> +static bool handle_tlbi_el1(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> +			    const struct sys_reg_desc *r)
> +{
> +	u64 virtual_vttbr = vcpu_read_sys_reg(vcpu, VTTBR_EL2);
> +	struct kvm_s2_mmu *mmu;
> +	int sys_encoding = sys_insn(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2);
> +
> +	/*
> +	 * TODO: Revisit this comment:
> +	 *
> +	 * If we can't find a shadow VMID, it is either the virtual
> +	 * VMID is for the host OS or the nested VM having the virtual
> +	 * VMID is never executed. (Note that we create a showdow VMID
> +	 * when entering a VM.) For the former, we can flush TLB
> +	 * entries belonging to the host OS in a VM. For the latter, we
> +	 * don't have to do anything. Since we can't differentiate
> +	 * between those cases, just do what we can do for the former.
> +	 */
> +
> +	mutex_lock(&vcpu->kvm->lock);
> +	mmu = lookup_s2_mmu(vcpu->kvm, virtual_vttbr, HCR_VM);
> +	if (mmu)
> +		kvm_call_hyp(__kvm_tlb_el1_instr,
> +			     mmu, p->regval, sys_encoding);
> +
> +	mmu = lookup_s2_mmu(vcpu->kvm, virtual_vttbr, 0);
> +	if (mmu)
> +		kvm_call_hyp(__kvm_tlb_el1_instr,
> +			     mmu, p->regval, sys_encoding);
> +	mutex_unlock(&vcpu->kvm->lock);
> +
> +	return true;
> +}
> +
>  /*
>   * AT instruction emulation
>   *
> @@ -2333,12 +2506,40 @@ static struct sys_reg_desc sys_insn_descs[] = {
>  	{ SYS_DESC(SYS_DC_CSW), access_dcsw },
>  	{ SYS_DESC(SYS_DC_CISW), access_dcsw },
>  
> +	SYS_INSN_TO_DESC(TLBI_VMALLE1IS, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAE1IS, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_ASIDE1IS, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAAE1IS, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VALE1IS, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAALE1IS, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VMALLE1, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAE1, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_ASIDE1, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAAE1, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VALE1, handle_tlbi_el1, forward_ttlb_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAALE1, handle_tlbi_el1, forward_ttlb_traps),
> +
>  	SYS_INSN_TO_DESC(AT_S1E2R, handle_s1e2, forward_nv_traps),
>  	SYS_INSN_TO_DESC(AT_S1E2W, handle_s1e2, forward_nv_traps),
>  	SYS_INSN_TO_DESC(AT_S12E1R, handle_s12r, forward_nv_traps),
>  	SYS_INSN_TO_DESC(AT_S12E1W, handle_s12w, forward_nv_traps),
>  	SYS_INSN_TO_DESC(AT_S12E0R, handle_s12r, forward_nv_traps),
>  	SYS_INSN_TO_DESC(AT_S12E0W, handle_s12w, forward_nv_traps),
> +
> +	SYS_INSN_TO_DESC(TLBI_IPAS2E1IS, handle_ipas2e1is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_IPAS2LE1IS, handle_ipas2e1is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_ALLE2IS, handle_alle2is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAE2IS, handle_vae2, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_ALLE1IS, handle_alle1is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_VALE2IS, handle_vae2, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_VMALLS12E1IS, handle_vmalls12e1is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_IPAS2E1, handle_ipas2e1is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_IPAS2LE1, handle_ipas2e1is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_ALLE2, handle_alle2is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_VAE2, handle_vae2, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_ALLE1, handle_alle1is, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_VALE2, handle_vae2, forward_nv_traps),
> +	SYS_INSN_TO_DESC(TLBI_VMALLS12E1, handle_vmalls12e1is, forward_nv_traps),
>  };
>  
>  static bool trap_dbgidr(struct kvm_vcpu *vcpu,
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index 6a7cba077bce..0ea79e543b29 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -51,7 +51,23 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot)
>   */
>  void kvm_flush_remote_tlbs(struct kvm *kvm)
>  {
> -	kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
> +	struct kvm_s2_mmu *mmu = &kvm->arch.mmu;
> +
> +	if (mmu == &kvm->arch.mmu) {
> +		/*
> +		 * For a normal (i.e. non-nested) guest, flush entries for the
> +		 * given VMID *
> +		 */
> +		kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
> +	} else {
> +		/*
> +		 * When supporting nested virtualization, we can have multiple
> +		 * VMIDs in play for each VCPU in the VM, so it's really not
> +		 * worth it to try to quiesce the system and flush all the
> +		 * VMIDs that may be in use, instead just nuke the whole thing.
> +		 */
> +		kvm_call_hyp(__kvm_flush_vm_context);
> +	}
>  }
>  
>  static void kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa)
> 

Cheers,

-- 
Julien Thierry

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