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remarkable-linux/arch/powerpc/kvm/book3s_pr_papr.c
Paul Mackerras 9308ab8e2d KVM: PPC: Book3S PR: Make HPT accesses and updates SMP-safe 
This adds a per-VM mutex to provide mutual exclusion between vcpus
for accesses to and updates of the guest hashed page table (HPT).
This also makes the code use single-byte writes to the HPT entry
when updating of the reference (R) and change (C) bits.  The reason
for doing this, rather than writing back the whole HPTE, is that on
non-PAPR virtual machines, the guest OS might be writing to the HPTE
concurrently, and writing back the whole HPTE might conflict with
that.  Also, real hardware does single-byte writes to update R and C.

The new mutex is taken in kvmppc_mmu_book3s_64_xlate() when reading
the HPT and updating R and/or C, and in the PAPR HPT update hcalls
(H_ENTER, H_REMOVE, etc.).  Having the mutex means that we don't need
to use a hypervisor lock bit in the HPT update hcalls, and we don't
need to be careful about the order in which the bytes of the HPTE are
updated by those hcalls.

The other change here is to make emulated TLB invalidations (tlbie)
effective across all vcpus.  To do this we call kvmppc_mmu_pte_vflush
for all vcpus in kvmppc_ppc_book3s_64_tlbie().

For 32-bit, this makes the setting of the accessed and dirty bits use
single-byte writes, and makes tlbie invalidate shadow HPTEs for all
vcpus.

With this, PR KVM can successfully run SMP guests.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-17 14:45:04 +02:00

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/*
* Copyright (C) 2011. Freescale Inc. All rights reserved.
*
* Authors:
* Alexander Graf <agraf@suse.de>
* Paul Mackerras <paulus@samba.org>
*
* Description:
*
* Hypercall handling for running PAPR guests in PR KVM on Book 3S
* processors.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*/
#include <linux/anon_inodes.h>
#include <asm/uaccess.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#define HPTE_SIZE 16 /* bytes per HPT entry */
static unsigned long get_pteg_addr(struct kvm_vcpu *vcpu, long pte_index)
{
struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
unsigned long pteg_addr;
pte_index <<= 4;
pte_index &= ((1 << ((vcpu_book3s->sdr1 & 0x1f) + 11)) - 1) << 7 | 0x70;
pteg_addr = vcpu_book3s->sdr1 & 0xfffffffffffc0000ULL;
pteg_addr |= pte_index;
return pteg_addr;
}
static int kvmppc_h_pr_enter(struct kvm_vcpu *vcpu)
{
long flags = kvmppc_get_gpr(vcpu, 4);
long pte_index = kvmppc_get_gpr(vcpu, 5);
unsigned long pteg[2 * 8];
unsigned long pteg_addr, i, *hpte;
long int ret;
i = pte_index & 7;
pte_index &= ~7UL;
pteg_addr = get_pteg_addr(vcpu, pte_index);
mutex_lock(&vcpu->kvm->arch.hpt_mutex);
copy_from_user(pteg, (void __user *)pteg_addr, sizeof(pteg));
hpte = pteg;
ret = H_PTEG_FULL;
if (likely((flags & H_EXACT) == 0)) {
for (i = 0; ; ++i) {
if (i == 8)
goto done;
if ((*hpte & HPTE_V_VALID) == 0)
break;
hpte += 2;
}
} else {
hpte += i * 2;
if (*hpte & HPTE_V_VALID)
goto done;
}
hpte[0] = kvmppc_get_gpr(vcpu, 6);
hpte[1] = kvmppc_get_gpr(vcpu, 7);
pteg_addr += i * HPTE_SIZE;
copy_to_user((void __user *)pteg_addr, hpte, HPTE_SIZE);
kvmppc_set_gpr(vcpu, 4, pte_index | i);
ret = H_SUCCESS;
done:
mutex_unlock(&vcpu->kvm->arch.hpt_mutex);
kvmppc_set_gpr(vcpu, 3, ret);
return EMULATE_DONE;
}
static int kvmppc_h_pr_remove(struct kvm_vcpu *vcpu)
{
unsigned long flags= kvmppc_get_gpr(vcpu, 4);
unsigned long pte_index = kvmppc_get_gpr(vcpu, 5);
unsigned long avpn = kvmppc_get_gpr(vcpu, 6);
unsigned long v = 0, pteg, rb;
unsigned long pte[2];
long int ret;
pteg = get_pteg_addr(vcpu, pte_index);
mutex_lock(&vcpu->kvm->arch.hpt_mutex);
copy_from_user(pte, (void __user *)pteg, sizeof(pte));
ret = H_NOT_FOUND;
if ((pte[0] & HPTE_V_VALID) == 0 ||
((flags & H_AVPN) && (pte[0] & ~0x7fUL) != avpn) ||
((flags & H_ANDCOND) && (pte[0] & avpn) != 0))
goto done;
copy_to_user((void __user *)pteg, &v, sizeof(v));
rb = compute_tlbie_rb(pte[0], pte[1], pte_index);
vcpu->arch.mmu.tlbie(vcpu, rb, rb & 1 ? true : false);
ret = H_SUCCESS;
kvmppc_set_gpr(vcpu, 4, pte[0]);
kvmppc_set_gpr(vcpu, 5, pte[1]);
done:
mutex_unlock(&vcpu->kvm->arch.hpt_mutex);
kvmppc_set_gpr(vcpu, 3, ret);
return EMULATE_DONE;
}
/* Request defs for kvmppc_h_pr_bulk_remove() */
#define H_BULK_REMOVE_TYPE 0xc000000000000000ULL
#define H_BULK_REMOVE_REQUEST 0x4000000000000000ULL
#define H_BULK_REMOVE_RESPONSE 0x8000000000000000ULL
#define H_BULK_REMOVE_END 0xc000000000000000ULL
#define H_BULK_REMOVE_CODE 0x3000000000000000ULL
#define H_BULK_REMOVE_SUCCESS 0x0000000000000000ULL
#define H_BULK_REMOVE_NOT_FOUND 0x1000000000000000ULL
#define H_BULK_REMOVE_PARM 0x2000000000000000ULL
#define H_BULK_REMOVE_HW 0x3000000000000000ULL
#define H_BULK_REMOVE_RC 0x0c00000000000000ULL
#define H_BULK_REMOVE_FLAGS 0x0300000000000000ULL
#define H_BULK_REMOVE_ABSOLUTE 0x0000000000000000ULL
#define H_BULK_REMOVE_ANDCOND 0x0100000000000000ULL
#define H_BULK_REMOVE_AVPN 0x0200000000000000ULL
#define H_BULK_REMOVE_PTEX 0x00ffffffffffffffULL
#define H_BULK_REMOVE_MAX_BATCH 4
static int kvmppc_h_pr_bulk_remove(struct kvm_vcpu *vcpu)
{
int i;
int paramnr = 4;
int ret = H_SUCCESS;
mutex_lock(&vcpu->kvm->arch.hpt_mutex);
for (i = 0; i < H_BULK_REMOVE_MAX_BATCH; i++) {
unsigned long tsh = kvmppc_get_gpr(vcpu, paramnr+(2*i));
unsigned long tsl = kvmppc_get_gpr(vcpu, paramnr+(2*i)+1);
unsigned long pteg, rb, flags;
unsigned long pte[2];
unsigned long v = 0;
if ((tsh & H_BULK_REMOVE_TYPE) == H_BULK_REMOVE_END) {
break; /* Exit success */
} else if ((tsh & H_BULK_REMOVE_TYPE) !=
H_BULK_REMOVE_REQUEST) {
ret = H_PARAMETER;
break; /* Exit fail */
}
tsh &= H_BULK_REMOVE_PTEX | H_BULK_REMOVE_FLAGS;
tsh |= H_BULK_REMOVE_RESPONSE;
if ((tsh & H_BULK_REMOVE_ANDCOND) &&
(tsh & H_BULK_REMOVE_AVPN)) {
tsh |= H_BULK_REMOVE_PARM;
kvmppc_set_gpr(vcpu, paramnr+(2*i), tsh);
ret = H_PARAMETER;
break; /* Exit fail */
}
pteg = get_pteg_addr(vcpu, tsh & H_BULK_REMOVE_PTEX);
copy_from_user(pte, (void __user *)pteg, sizeof(pte));
/* tsl = AVPN */
flags = (tsh & H_BULK_REMOVE_FLAGS) >> 26;
if ((pte[0] & HPTE_V_VALID) == 0 ||
((flags & H_AVPN) && (pte[0] & ~0x7fUL) != tsl) ||
((flags & H_ANDCOND) && (pte[0] & tsl) != 0)) {
tsh |= H_BULK_REMOVE_NOT_FOUND;
} else {
/* Splat the pteg in (userland) hpt */
copy_to_user((void __user *)pteg, &v, sizeof(v));
rb = compute_tlbie_rb(pte[0], pte[1],
tsh & H_BULK_REMOVE_PTEX);
vcpu->arch.mmu.tlbie(vcpu, rb, rb & 1 ? true : false);
tsh |= H_BULK_REMOVE_SUCCESS;
tsh |= (pte[1] & (HPTE_R_C | HPTE_R_R)) << 43;
}
kvmppc_set_gpr(vcpu, paramnr+(2*i), tsh);
}
mutex_unlock(&vcpu->kvm->arch.hpt_mutex);
kvmppc_set_gpr(vcpu, 3, ret);
return EMULATE_DONE;
}
static int kvmppc_h_pr_protect(struct kvm_vcpu *vcpu)
{
unsigned long flags = kvmppc_get_gpr(vcpu, 4);
unsigned long pte_index = kvmppc_get_gpr(vcpu, 5);
unsigned long avpn = kvmppc_get_gpr(vcpu, 6);
unsigned long rb, pteg, r, v;
unsigned long pte[2];
long int ret;
pteg = get_pteg_addr(vcpu, pte_index);
mutex_lock(&vcpu->kvm->arch.hpt_mutex);
copy_from_user(pte, (void __user *)pteg, sizeof(pte));
ret = H_NOT_FOUND;
if ((pte[0] & HPTE_V_VALID) == 0 ||
((flags & H_AVPN) && (pte[0] & ~0x7fUL) != avpn))
goto done;
v = pte[0];
r = pte[1];
r &= ~(HPTE_R_PP0 | HPTE_R_PP | HPTE_R_N | HPTE_R_KEY_HI |
HPTE_R_KEY_LO);
r |= (flags << 55) & HPTE_R_PP0;
r |= (flags << 48) & HPTE_R_KEY_HI;
r |= flags & (HPTE_R_PP | HPTE_R_N | HPTE_R_KEY_LO);
pte[1] = r;
rb = compute_tlbie_rb(v, r, pte_index);
vcpu->arch.mmu.tlbie(vcpu, rb, rb & 1 ? true : false);
copy_to_user((void __user *)pteg, pte, sizeof(pte));
ret = H_SUCCESS;
done:
mutex_unlock(&vcpu->kvm->arch.hpt_mutex);
kvmppc_set_gpr(vcpu, 3, ret);
return EMULATE_DONE;
}
static int kvmppc_h_pr_put_tce(struct kvm_vcpu *vcpu)
{
unsigned long liobn = kvmppc_get_gpr(vcpu, 4);
unsigned long ioba = kvmppc_get_gpr(vcpu, 5);
unsigned long tce = kvmppc_get_gpr(vcpu, 6);
long rc;
rc = kvmppc_h_put_tce(vcpu, liobn, ioba, tce);
if (rc == H_TOO_HARD)
return EMULATE_FAIL;
kvmppc_set_gpr(vcpu, 3, rc);
return EMULATE_DONE;
}
static int kvmppc_h_pr_xics_hcall(struct kvm_vcpu *vcpu, u32 cmd)
{
long rc = kvmppc_xics_hcall(vcpu, cmd);
kvmppc_set_gpr(vcpu, 3, rc);
return EMULATE_DONE;
}
int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd)
{
switch (cmd) {
case H_ENTER:
return kvmppc_h_pr_enter(vcpu);
case H_REMOVE:
return kvmppc_h_pr_remove(vcpu);
case H_PROTECT:
return kvmppc_h_pr_protect(vcpu);
case H_BULK_REMOVE:
return kvmppc_h_pr_bulk_remove(vcpu);
case H_PUT_TCE:
return kvmppc_h_pr_put_tce(vcpu);
case H_CEDE:
vcpu->arch.shared->msr |= MSR_EE;
kvm_vcpu_block(vcpu);
clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
vcpu->stat.halt_wakeup++;
return EMULATE_DONE;
case H_XIRR:
case H_CPPR:
case H_EOI:
case H_IPI:
case H_IPOLL:
case H_XIRR_X:
if (kvmppc_xics_enabled(vcpu))
return kvmppc_h_pr_xics_hcall(vcpu, cmd);
break;
case H_RTAS:
if (list_empty(&vcpu->kvm->arch.rtas_tokens))
return RESUME_HOST;
if (kvmppc_rtas_hcall(vcpu))
break;
kvmppc_set_gpr(vcpu, 3, 0);
return EMULATE_DONE;
}
return EMULATE_FAIL;
}
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