From c3edd62851098e6417786193ed9e9341781fcf57 Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Thu, 12 Feb 2015 18:09:31 +0100 Subject: [PATCH] s390x/mmu: Add function for accessing guest memory According to the POP specification, the parameter blocks of various functions like the IO instructions are accessed with logical addresses. Thus we need a function that can read or write a buffer from/to the guest's logical address space. This patch now provides a function that can be used to access virtual guest memory by using the mmu_translate function of QEMU to convert the virtual addresses to physical. Signed-off-by: Thomas Huth Signed-off-by: Jens Freimann Reviewed-by: Cornelia Huck Reviewed-by: David Hildenbrand Signed-off-by: Christian Borntraeger --- target-s390x/cpu.h | 11 +++++ target-s390x/mmu_helper.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h index f8cea30..a9ab587 100644 --- a/target-s390x/cpu.h +++ b/target-s390x/cpu.h @@ -287,6 +287,7 @@ typedef struct CPUS390XState { #define FLAG_MASK_32 0x00001000 /* Control register 0 bits */ +#define CR0_LOWPROT 0x0000000010000000ULL #define CR0_EDAT 0x0000000000800000ULL static inline int cpu_mmu_index (CPUS390XState *env) @@ -897,6 +898,16 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code); uint32_t calc_cc(CPUS390XState *env, uint32_t cc_op, uint64_t src, uint64_t dst, uint64_t vr); +int s390_cpu_virt_mem_rw(S390CPU *cpu, vaddr laddr, void *hostbuf, int len, + bool is_write); + +#define s390_cpu_virt_mem_read(cpu, laddr, dest, len) \ + s390_cpu_virt_mem_rw(cpu, laddr, dest, len, false) +#define s390_cpu_virt_mem_write(cpu, laddr, dest, len) \ + s390_cpu_virt_mem_rw(cpu, laddr, dest, len, true) +#define s390_cpu_virt_mem_check_write(cpu, laddr, len) \ + s390_cpu_virt_mem_rw(cpu, laddr, NULL, len, true) + /* The value of the TOD clock for 1.1.1970. */ #define TOD_UNIX_EPOCH 0x7d91048bca000000ULL diff --git a/target-s390x/mmu_helper.c b/target-s390x/mmu_helper.c index a1ee992..b061c85 100644 --- a/target-s390x/mmu_helper.c +++ b/target-s390x/mmu_helper.c @@ -15,6 +15,9 @@ * GNU General Public License for more details. */ +#include "qemu/error-report.h" +#include "exec/address-spaces.h" +#include "sysemu/kvm.h" #include "cpu.h" /* #define DEBUG_S390 */ @@ -368,3 +371,102 @@ int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc, return r; } + +/** + * lowprot_enabled: Check whether low-address protection is enabled + */ +static bool lowprot_enabled(const CPUS390XState *env) +{ + if (!(env->cregs[0] & CR0_LOWPROT)) { + return false; + } + if (!(env->psw.mask & PSW_MASK_DAT)) { + return true; + } + + /* Check the private-space control bit */ + switch (env->psw.mask & PSW_MASK_ASC) { + case PSW_ASC_PRIMARY: + return !(env->cregs[1] & _ASCE_PRIVATE_SPACE); + case PSW_ASC_SECONDARY: + return !(env->cregs[7] & _ASCE_PRIVATE_SPACE); + case PSW_ASC_HOME: + return !(env->cregs[13] & _ASCE_PRIVATE_SPACE); + default: + /* We don't support access register mode */ + error_report("unsupported addressing mode"); + exit(1); + } +} + +/** + * translate_pages: Translate a set of consecutive logical page addresses + * to absolute addresses + */ +static int translate_pages(S390CPU *cpu, vaddr addr, int nr_pages, + target_ulong *pages, bool is_write) +{ + bool lowprot = is_write && lowprot_enabled(&cpu->env); + uint64_t asc = cpu->env.psw.mask & PSW_MASK_ASC; + CPUS390XState *env = &cpu->env; + int ret, i, pflags; + + for (i = 0; i < nr_pages; i++) { + /* Low-address protection? */ + if (lowprot && (addr < 512 || (addr >= 4096 && addr < 4096 + 512))) { + trigger_access_exception(env, PGM_PROTECTION, ILEN_LATER_INC, 0); + return -EACCES; + } + ret = mmu_translate(env, addr, is_write, asc, &pages[i], &pflags, true); + if (ret) { + return ret; + } + if (!address_space_access_valid(&address_space_memory, pages[i], + TARGET_PAGE_SIZE, is_write)) { + program_interrupt(env, PGM_ADDRESSING, 0); + return -EFAULT; + } + addr += TARGET_PAGE_SIZE; + } + + return 0; +} + +/** + * s390_cpu_virt_mem_rw: + * @laddr: the logical start address + * @hostbuf: buffer in host memory. NULL = do only checks w/o copying + * @len: length that should be transfered + * @is_write: true = write, false = read + * Returns: 0 on success, non-zero if an exception occured + * + * Copy from/to guest memory using logical addresses. Note that we inject a + * program interrupt in case there is an error while accessing the memory. + */ +int s390_cpu_virt_mem_rw(S390CPU *cpu, vaddr laddr, void *hostbuf, + int len, bool is_write) +{ + int currlen, nr_pages, i; + target_ulong *pages; + int ret; + + nr_pages = (((laddr & ~TARGET_PAGE_MASK) + len - 1) >> TARGET_PAGE_BITS) + + 1; + pages = g_malloc(nr_pages * sizeof(*pages)); + + ret = translate_pages(cpu, laddr, nr_pages, pages, is_write); + if (ret == 0 && hostbuf != NULL) { + /* Copy data by stepping through the area page by page */ + for (i = 0; i < nr_pages; i++) { + currlen = MIN(len, TARGET_PAGE_SIZE - (laddr % TARGET_PAGE_SIZE)); + cpu_physical_memory_rw(pages[i] | (laddr & ~TARGET_PAGE_MASK), + hostbuf, currlen, is_write); + laddr += currlen; + hostbuf += currlen; + len -= currlen; + } + } + + g_free(pages); + return ret; +} -- 2.7.4