Commit a7e19ab5 authored by David Hildenbrand's avatar David Hildenbrand Committed by Christian Borntraeger
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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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 11ddcd41
......@@ -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 */
......
......@@ -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);
......
......@@ -27,6 +27,7 @@
#include <asm/io.h>
#include <asm/ptrace.h>
#include <asm/compat.h>
#include <asm/sclp.h>
#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, &reg1, &reg2);
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(&current->mm->mmap_sem);
rc = get_guest_storage_key(current->mm, addr, &key);
up_read(&current->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, &reg1, &reg2);
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(&current->mm->mmap_sem);
rc = reset_guest_reference_bit(current->mm, addr);
up_read(&current->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, &reg1, &reg2);
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(&current->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(&current->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,
......
......@@ -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)
{
......
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