diff mbox series

[v4,23/32] KVM: PPC: Book3S HV: Implement H_TLB_INVALIDATE hcall

Message ID 1538654169-15602-24-git-send-email-paulus@ozlabs.org
State Superseded
Headers show
Series KVM: PPC: Book3S HV: Nested HV virtualization | expand

Commit Message

Paul Mackerras Oct. 4, 2018, 11:56 a.m. UTC 
From: Suraj Jitindar Singh <sjitindarsingh@gmail.com>

When running a nested (L2) guest the guest (L1) hypervisor will use
the H_TLB_INVALIDATE hcall when it needs to change the partition
scoped page tables or the partition table which it manages.  It will
use this hcall in the situations where it would use a partition-scoped
tlbie instruction if it were running in hypervisor mode.

The H_TLB_INVALIDATE hcall can invalidate different scopes:

Invalidate TLB for a given target address:
- This invalidates a single L2 -> L1 pte
- We need to invalidate any L2 -> L0 shadow_pgtable ptes which map the L2
  address space which is being invalidated. This is because a single
  L2 -> L1 pte may have been mapped with more than one pte in the
  L2 -> L0 page tables.

Invalidate the entire TLB for a given LPID or for all LPIDs:
- Invalidate the entire shadow_pgtable for a given nested guest, or
  for all nested guests.

Invalidate the PWC (page walk cache) for a given LPID or for all LPIDs:
- We don't cache the PWC, so nothing to do.

Invalidate the entire TLB, PWC and partition table for a given/all LPIDs:
- Here we re-read the partition table entry and remove the nested state
  for any nested guest for which the first doubleword of the partition
  table entry is now zero.

The H_TLB_INVALIDATE hcall takes as parameters the tlbie instruction
word (of which only the RIC, PRS and R fields are used), the rS value
(giving the lpid, where required) and the rB value (giving the IS, AP
and EPN values).

[paulus@ozlabs.org - adapted to having the partition table in guest
memory, added the H_TLB_INVALIDATE implementation, removed tlbie
instruction emulation, reworded the commit message.]

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |  12 ++
 arch/powerpc/include/asm/kvm_book3s.h         |   1 +
 arch/powerpc/include/asm/ppc-opcode.h         |   1 +
 arch/powerpc/kvm/book3s_emulate.c             |   1 -
 arch/powerpc/kvm/book3s_hv.c                  |   3 +
 arch/powerpc/kvm/book3s_hv_nested.c           | 196 +++++++++++++++++++++++++-
 6 files changed, 212 insertions(+), 2 deletions(-)

Comments

David Gibson Oct. 5, 2018, 3:40 a.m. UTC | #1 
On Thu, Oct 04, 2018 at 09:56:00PM +1000, Paul Mackerras wrote:
11;rgb:ffff/ffff/ffff> From: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> 
> When running a nested (L2) guest the guest (L1) hypervisor will use
> the H_TLB_INVALIDATE hcall when it needs to change the partition
> scoped page tables or the partition table which it manages.  It will
> use this hcall in the situations where it would use a partition-scoped
> tlbie instruction if it were running in hypervisor mode.
> 
> The H_TLB_INVALIDATE hcall can invalidate different scopes:
> 
> Invalidate TLB for a given target address:
> - This invalidates a single L2 -> L1 pte
> - We need to invalidate any L2 -> L0 shadow_pgtable ptes which map the L2
>   address space which is being invalidated. This is because a single
>   L2 -> L1 pte may have been mapped with more than one pte in the
>   L2 -> L0 page tables.
> 
> Invalidate the entire TLB for a given LPID or for all LPIDs:
> - Invalidate the entire shadow_pgtable for a given nested guest, or
>   for all nested guests.
> 
> Invalidate the PWC (page walk cache) for a given LPID or for all LPIDs:
> - We don't cache the PWC, so nothing to do.
> 
> Invalidate the entire TLB, PWC and partition table for a given/all LPIDs:
> - Here we re-read the partition table entry and remove the nested state
>   for any nested guest for which the first doubleword of the partition
>   table entry is now zero.
> 
> The H_TLB_INVALIDATE hcall takes as parameters the tlbie instruction
> word (of which only the RIC, PRS and R fields are used), the rS value
> (giving the lpid, where required) and the rB value (giving the IS, AP
> and EPN values).
> 
> [paulus@ozlabs.org - adapted to having the partition table in guest
> memory, added the H_TLB_INVALIDATE implementation, removed tlbie
> instruction emulation, reworded the commit message.]
> 
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

That said, there's one change I think could make it substantially
easier to read..

[snip]
> +static int kvmhv_emulate_tlbie_tlb_addr(struct kvm_vcpu *vcpu, int lpid,
> +					int ap, long epn)
> +{
> +	struct kvm *kvm = vcpu->kvm;
> +	struct kvm_nested_guest *gp;
> +	long npages;
> +	int shift;
> +	unsigned long addr;
> +
> +	shift = ap_to_shift(ap);
> +	addr = epn << 12;
> +	if (shift < 0)
> +		/* Invalid ap encoding */
> +		return -EINVAL;
> +
> +	addr &= ~((1UL << shift) - 1);
> +	npages = 1UL << (shift - PAGE_SHIFT);
> +
> +	gp = kvmhv_get_nested(kvm, lpid, false);
> +	if (!gp) /* No such guest -> nothing to do */
> +		return 0;
> +	mutex_lock(&gp->tlb_lock);
> +
> +	/* There may be more than one host page backing this single guest pte */
> +	do {
> +		kvmhv_invalidate_shadow_pte(vcpu, gp, addr, &shift);
> +
> +		npages -= 1UL << (shift - PAGE_SHIFT);
> +		addr += 1UL << shift;

I read this about 6 times before realizing that 'shift' here has a
different value to what it did before the loop (which it has to in
order to be correct).  I'd suggest a loop local variable with a
different name (maybe 'shadow_shift') to make that more obvious.
diff mbox series

Patch

diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index b3520b5..66db23e 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -203,6 +203,18 @@  static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
 	BUG();
 }
 
+static inline unsigned int ap_to_shift(unsigned long ap)
+{
+	int psize;
+
+	for (psize = 0; psize < MMU_PAGE_COUNT; psize++) {
+		if (mmu_psize_defs[psize].ap == ap)
+			return mmu_psize_defs[psize].shift;
+	}
+
+	return -1;
+}
+
 static inline unsigned long get_sllp_encoding(int psize)
 {
 	unsigned long sllp;
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index d7aeb6f..09f8e9b 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -301,6 +301,7 @@  long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
 void kvmhv_set_ptbl_entry(unsigned int lpid, u64 dw0, u64 dw1);
 void kvmhv_release_all_nested(struct kvm *kvm);
 long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
+long kvmhv_do_nested_tlbie(struct kvm_vcpu *vcpu);
 int kvmhv_run_single_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu,
 			  u64 time_limit, unsigned long lpcr);
 void kvmhv_save_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr);
diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 665af14..6093bc8 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -104,6 +104,7 @@ 
 #define OP_31_XOP_LHZUX     311
 #define OP_31_XOP_MSGSNDP   142
 #define OP_31_XOP_MSGCLRP   174
+#define OP_31_XOP_TLBIE     306
 #define OP_31_XOP_MFSPR     339
 #define OP_31_XOP_LWAX      341
 #define OP_31_XOP_LHAX      343
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index 2654df2..8c7e933 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -36,7 +36,6 @@ 
 #define OP_31_XOP_MTSR		210
 #define OP_31_XOP_MTSRIN	242
 #define OP_31_XOP_TLBIEL	274
-#define OP_31_XOP_TLBIE		306
 /* Opcode is officially reserved, reuse it as sc 1 when sc 1 doesn't trap */
 #define OP_31_XOP_FAKE_SC1	308
 #define OP_31_XOP_SLBMTE	402
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 2d8209a..ba58883 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -974,6 +974,9 @@  int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
 		break;
 	case H_TLB_INVALIDATE:
 		ret = H_FUNCTION;
+		if (!vcpu->kvm->arch.nested_enable)
+			break;
+		ret = kvmhv_do_nested_tlbie(vcpu);
 		break;
 
 	default:
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 3947aa5..26151e8 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -475,7 +475,7 @@  void kvmhv_release_all_nested(struct kvm *kvm)
 }
 
 /* caller must hold gp->tlb_lock */
-void kvmhv_flush_nested(struct kvm_nested_guest *gp)
+static void kvmhv_flush_nested(struct kvm_nested_guest *gp)
 {
 	struct kvm *kvm = gp->l1_host;
 
@@ -683,6 +683,200 @@  static bool kvmhv_invalidate_shadow_pte(struct kvm_vcpu *vcpu,
 	return ret;
 }
 
+static inline int get_ric(unsigned int instr)
+{
+	return (instr >> 18) & 0x3;
+}
+
+static inline int get_prs(unsigned int instr)
+{
+	return (instr >> 17) & 0x1;
+}
+
+static inline int get_r(unsigned int instr)
+{
+	return (instr >> 16) & 0x1;
+}
+
+static inline int get_lpid(unsigned long r_val)
+{
+	return r_val & 0xffffffff;
+}
+
+static inline int get_is(unsigned long r_val)
+{
+	return (r_val >> 10) & 0x3;
+}
+
+static inline int get_ap(unsigned long r_val)
+{
+	return (r_val >> 5) & 0x7;
+}
+
+static inline long get_epn(unsigned long r_val)
+{
+	return r_val >> 12;
+}
+
+static int kvmhv_emulate_tlbie_tlb_addr(struct kvm_vcpu *vcpu, int lpid,
+					int ap, long epn)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_nested_guest *gp;
+	long npages;
+	int shift;
+	unsigned long addr;
+
+	shift = ap_to_shift(ap);
+	addr = epn << 12;
+	if (shift < 0)
+		/* Invalid ap encoding */
+		return -EINVAL;
+
+	addr &= ~((1UL << shift) - 1);
+	npages = 1UL << (shift - PAGE_SHIFT);
+
+	gp = kvmhv_get_nested(kvm, lpid, false);
+	if (!gp) /* No such guest -> nothing to do */
+		return 0;
+	mutex_lock(&gp->tlb_lock);
+
+	/* There may be more than one host page backing this single guest pte */
+	do {
+		kvmhv_invalidate_shadow_pte(vcpu, gp, addr, &shift);
+
+		npages -= 1UL << (shift - PAGE_SHIFT);
+		addr += 1UL << shift;
+	} while (npages > 0);
+
+	mutex_unlock(&gp->tlb_lock);
+	kvmhv_put_nested(gp);
+	return 0;
+}
+
+static void kvmhv_emulate_tlbie_lpid(struct kvm_vcpu *vcpu,
+				     struct kvm_nested_guest *gp, int ric)
+{
+	struct kvm *kvm = vcpu->kvm;
+
+	mutex_lock(&gp->tlb_lock);
+	switch (ric) {
+	case 0:
+		/* Invalidate TLB */
+		spin_lock(&kvm->mmu_lock);
+		kvmppc_free_pgtable_radix(kvm, gp->shadow_pgtable,
+					  gp->shadow_lpid);
+		radix__flush_tlb_lpid(gp->shadow_lpid);
+		spin_unlock(&kvm->mmu_lock);
+		break;
+	case 1:
+		/*
+		 * Invalidate PWC
+		 * We don't cache this -> nothing to do
+		 */
+		break;
+	case 2:
+		/* Invalidate TLB, PWC and caching of partition table entries */
+		kvmhv_flush_nested(gp);
+		break;
+	default:
+		break;
+	}
+	mutex_unlock(&gp->tlb_lock);
+}
+
+static void kvmhv_emulate_tlbie_all_lpid(struct kvm_vcpu *vcpu, int ric)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_nested_guest *gp;
+	int i;
+
+	spin_lock(&kvm->mmu_lock);
+	for (i = 0; i <= kvm->arch.max_nested_lpid; i++) {
+		gp = kvm->arch.nested_guests[i];
+		if (gp) {
+			spin_unlock(&kvm->mmu_lock);
+			kvmhv_emulate_tlbie_lpid(vcpu, gp, ric);
+			spin_lock(&kvm->mmu_lock);
+		}
+	}
+	spin_unlock(&kvm->mmu_lock);
+}
+
+static int kvmhv_emulate_priv_tlbie(struct kvm_vcpu *vcpu, unsigned int instr,
+				    unsigned long rsval, unsigned long rbval)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_nested_guest *gp;
+	int r, ric, prs, is, ap;
+	int lpid;
+	long epn;
+	int ret = 0;
+
+	ric = get_ric(instr);
+	prs = get_prs(instr);
+	r = get_r(instr);
+	lpid = get_lpid(rsval);
+	is = get_is(rbval);
+
+	/*
+	 * These cases are invalid and are not handled:
+	 * r   != 1 -> Only radix supported
+	 * prs == 1 -> Not HV privileged
+	 * ric == 3 -> No cluster bombs for radix
+	 * is  == 1 -> Partition scoped translations not associated with pid
+	 * (!is) && (ric == 1 || ric == 2) -> Not supported by ISA
+	 */
+	if ((!r) || (prs) || (ric == 3) || (is == 1) ||
+	    ((!is) && (ric == 1 || ric == 2)))
+		return -EINVAL;
+
+	switch (is) {
+	case 0:
+		/*
+		 * We know ric == 0
+		 * Invalidate TLB for a given target address
+		 */
+		epn = get_epn(rbval);
+		ap = get_ap(rbval);
+		ret = kvmhv_emulate_tlbie_tlb_addr(vcpu, lpid, ap, epn);
+		break;
+	case 2:
+		/* Invalidate matching LPID */
+		gp = kvmhv_get_nested(kvm, lpid, false);
+		if (gp) {
+			kvmhv_emulate_tlbie_lpid(vcpu, gp, ric);
+			kvmhv_put_nested(gp);
+		}
+		break;
+	case 3:
+		/* Invalidate ALL LPIDs */
+		kvmhv_emulate_tlbie_all_lpid(vcpu, ric);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+/*
+ * This handles the H_TLB_INVALIDATE hcall.
+ * Parameters are (r4) tlbie instruction code, (r5) rS contents,
+ * (r6) rB contents.
+ */
+long kvmhv_do_nested_tlbie(struct kvm_vcpu *vcpu)
+{
+	int ret;
+
+	ret = kvmhv_emulate_priv_tlbie(vcpu, kvmppc_get_gpr(vcpu, 4),
+			kvmppc_get_gpr(vcpu, 5), kvmppc_get_gpr(vcpu, 6));
+	if (ret)
+		return H_PARAMETER;
+	return H_SUCCESS;
+}
+
 /* Used to convert a nested guest real address to a L1 guest real address */
 static int kvmhv_translate_addr_nested(struct kvm_vcpu *vcpu,
 				       struct kvm_nested_guest *gp,