From a7e19ab55ffdd82f1a8d12694b9a0c0beeef534c Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Tue, 10 May 2016 09:50:21 +0200 Subject: [PATCH] KVM: s390: handle missing storage-key facility Without the storage-key facility, SIE won't interpret SSKE, ISKE and RRBE for us. So let's add proper interception handlers that will be called if lazy sske cannot be enabled. Reviewed-by: Christian Borntraeger Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/page.h | 7 +- arch/s390/include/asm/pgtable.h | 1 + arch/s390/kvm/priv.c | 150 ++++++++++++++++++++++++++++++-- arch/s390/mm/pgtable.c | 37 ++++++++ 4 files changed, 184 insertions(+), 11 deletions(-) diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h index 53eacbd4f09b..f874e7d51c19 100644 --- a/arch/s390/include/asm/page.h +++ b/arch/s390/include/asm/page.h @@ -109,13 +109,14 @@ static inline unsigned char page_get_storage_key(unsigned long addr) static inline int page_reset_referenced(unsigned long addr) { - unsigned int ipm; + int cc; asm volatile( " rrbe 0,%1\n" " ipm %0\n" - : "=d" (ipm) : "a" (addr) : "cc"); - return !!(ipm & 0x20000000); + " srl %0,28\n" + : "=d" (cc) : "a" (addr) : "cc"); + return cc; } /* Bits int the storage key */ diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 2f6702e27db9..9951e7e59756 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -896,6 +896,7 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr, unsigned char key, unsigned char *oldkey, bool nq, bool mr, bool mc); +int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr); int get_guest_storage_key(struct mm_struct *mm, unsigned long addr, unsigned char *key); diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 6745c2a602c3..3db3be139992 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -27,6 +27,7 @@ #include #include #include +#include #include "gaccess.h" #include "kvm-s390.h" #include "trace.h" @@ -164,8 +165,7 @@ static int __skey_check_enable(struct kvm_vcpu *vcpu) return rc; } - -static int handle_skey(struct kvm_vcpu *vcpu) +static int try_handle_skey(struct kvm_vcpu *vcpu) { int rc; @@ -173,12 +173,146 @@ static int handle_skey(struct kvm_vcpu *vcpu) rc = __skey_check_enable(vcpu); if (rc) return rc; - + if (sclp.has_skey) { + /* with storage-key facility, SIE interprets it for us */ + kvm_s390_retry_instr(vcpu); + VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation"); + return -EAGAIN; + } if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); + return 0; +} - kvm_s390_retry_instr(vcpu); - VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation"); +static int handle_iske(struct kvm_vcpu *vcpu) +{ + unsigned long addr; + unsigned char key; + int reg1, reg2; + int rc; + + rc = try_handle_skey(vcpu); + if (rc) + return rc != -EAGAIN ? rc : 0; + + kvm_s390_get_regs_rre(vcpu, ®1, ®2); + + addr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK; + addr = kvm_s390_logical_to_effective(vcpu, addr); + addr = kvm_s390_real_to_abs(vcpu, addr); + addr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(addr)); + if (kvm_is_error_hva(addr)) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + + down_read(¤t->mm->mmap_sem); + rc = get_guest_storage_key(current->mm, addr, &key); + up_read(¤t->mm->mmap_sem); + if (rc) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + vcpu->run->s.regs.gprs[reg1] &= ~0xff; + vcpu->run->s.regs.gprs[reg1] |= key; + return 0; +} + +static int handle_rrbe(struct kvm_vcpu *vcpu) +{ + unsigned long addr; + int reg1, reg2; + int rc; + + rc = try_handle_skey(vcpu); + if (rc) + return rc != -EAGAIN ? rc : 0; + + kvm_s390_get_regs_rre(vcpu, ®1, ®2); + + addr = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK; + addr = kvm_s390_logical_to_effective(vcpu, addr); + addr = kvm_s390_real_to_abs(vcpu, addr); + addr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(addr)); + if (kvm_is_error_hva(addr)) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + + down_read(¤t->mm->mmap_sem); + rc = reset_guest_reference_bit(current->mm, addr); + up_read(¤t->mm->mmap_sem); + if (rc < 0) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + + kvm_s390_set_psw_cc(vcpu, rc); + return 0; +} + +#define SSKE_NQ 0x8 +#define SSKE_MR 0x4 +#define SSKE_MC 0x2 +#define SSKE_MB 0x1 +static int handle_sske(struct kvm_vcpu *vcpu) +{ + unsigned char m3 = vcpu->arch.sie_block->ipb >> 28; + unsigned long start, end; + unsigned char key, oldkey; + int reg1, reg2; + int rc; + + rc = try_handle_skey(vcpu); + if (rc) + return rc != -EAGAIN ? rc : 0; + + if (!test_kvm_facility(vcpu->kvm, 8)) + m3 &= ~SSKE_MB; + if (!test_kvm_facility(vcpu->kvm, 10)) + m3 &= ~(SSKE_MC | SSKE_MR); + if (!test_kvm_facility(vcpu->kvm, 14)) + m3 &= ~SSKE_NQ; + + kvm_s390_get_regs_rre(vcpu, ®1, ®2); + + key = vcpu->run->s.regs.gprs[reg1] & 0xfe; + start = vcpu->run->s.regs.gprs[reg2] & PAGE_MASK; + start = kvm_s390_logical_to_effective(vcpu, start); + if (m3 & SSKE_MB) { + /* start already designates an absolute address */ + end = (start + (1UL << 20)) & ~((1UL << 20) - 1); + } else { + start = kvm_s390_real_to_abs(vcpu, start); + end = start + PAGE_SIZE; + } + + while (start != end) { + unsigned long addr = gfn_to_hva(vcpu->kvm, gpa_to_gfn(start)); + + if (kvm_is_error_hva(addr)) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + + down_read(¤t->mm->mmap_sem); + rc = cond_set_guest_storage_key(current->mm, addr, key, &oldkey, + m3 & SSKE_NQ, m3 & SSKE_MR, + m3 & SSKE_MC); + up_read(¤t->mm->mmap_sem); + if (rc < 0) + return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); + start += PAGE_SIZE; + }; + + if (m3 & (SSKE_MC | SSKE_MR)) { + if (m3 & SSKE_MB) { + /* skey in reg1 is unpredictable */ + kvm_s390_set_psw_cc(vcpu, 3); + } else { + kvm_s390_set_psw_cc(vcpu, rc); + vcpu->run->s.regs.gprs[reg1] &= ~0xff00UL; + vcpu->run->s.regs.gprs[reg1] |= (u64) oldkey << 8; + } + } + if (m3 & SSKE_MB) { + if (psw_bits(vcpu->arch.sie_block->gpsw).eaba == PSW_AMODE_64BIT) + vcpu->run->s.regs.gprs[reg2] &= ~PAGE_MASK; + else + vcpu->run->s.regs.gprs[reg2] &= ~0xfffff000UL; + end = kvm_s390_logical_to_effective(vcpu, end); + vcpu->run->s.regs.gprs[reg2] |= end; + } return 0; } @@ -586,9 +720,9 @@ static const intercept_handler_t b2_handlers[256] = { [0x11] = handle_store_prefix, [0x12] = handle_store_cpu_address, [0x21] = handle_ipte_interlock, - [0x29] = handle_skey, - [0x2a] = handle_skey, - [0x2b] = handle_skey, + [0x29] = handle_iske, + [0x2a] = handle_rrbe, + [0x2b] = handle_sske, [0x2c] = handle_test_block, [0x30] = handle_io_inst, [0x31] = handle_io_inst, diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index e791e8b27fd2..fa286d0c0f2d 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -572,6 +572,43 @@ int cond_set_guest_storage_key(struct mm_struct *mm, unsigned long addr, } EXPORT_SYMBOL(cond_set_guest_storage_key); +/** + * Reset a guest reference bit (rrbe), returning the reference and changed bit. + * + * Returns < 0 in case of error, otherwise the cc to be reported to the guest. + */ +int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr) +{ + spinlock_t *ptl; + pgste_t old, new; + pte_t *ptep; + int cc = 0; + + ptep = get_locked_pte(mm, addr, &ptl); + if (unlikely(!ptep)) + return -EFAULT; + + new = old = pgste_get_lock(ptep); + /* Reset guest reference bit only */ + pgste_val(new) &= ~PGSTE_GR_BIT; + + if (!(pte_val(*ptep) & _PAGE_INVALID)) { + cc = page_reset_referenced(pte_val(*ptep) & PAGE_MASK); + /* Merge real referenced bit into host-set */ + pgste_val(new) |= ((unsigned long) cc << 53) & PGSTE_HR_BIT; + } + /* Reflect guest's logical view, not physical */ + cc |= (pgste_val(old) & (PGSTE_GR_BIT | PGSTE_GC_BIT)) >> 49; + /* Changing the guest storage key is considered a change of the page */ + if ((pgste_val(new) ^ pgste_val(old)) & PGSTE_GR_BIT) + pgste_val(new) |= PGSTE_UC_BIT; + + pgste_set_unlock(ptep, new); + pte_unmap_unlock(ptep, ptl); + return 0; +} +EXPORT_SYMBOL(reset_guest_reference_bit); + int get_guest_storage_key(struct mm_struct *mm, unsigned long addr, unsigned char *key) { -- 2.45.2