diff options
Diffstat (limited to 'arch/s390/kvm/pv.c')
| -rw-r--r-- | arch/s390/kvm/pv.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index cc7c9599f43e..e9912113879c 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -7,6 +7,7 @@ */ #include <linux/kvm.h> #include <linux/kvm_host.h> +#include <linux/minmax.h> #include <linux/pagemap.h> #include <linux/sched/signal.h> #include <asm/gmap.h> @@ -298,3 +299,184 @@ int kvm_s390_pv_set_cpu_state(struct kvm_vcpu *vcpu, u8 state) return -EINVAL; return 0; } + +/* Size of the cache for the storage state dump data. 1MB for now */ +#define DUMP_BUFF_LEN HPAGE_SIZE + +/** + * kvm_s390_pv_dump_stor_state + * + * @kvm: pointer to the guest's KVM struct + * @buff_user: Userspace pointer where we will write the results to + * @gaddr: Starting absolute guest address for which the storage state + * is requested. + * @buff_user_len: Length of the buff_user buffer + * @rc: Pointer to where the uvcb return code is stored + * @rrc: Pointer to where the uvcb return reason code is stored + * + * Stores buff_len bytes of tweak component values to buff_user + * starting with the 1MB block specified by the absolute guest address + * (gaddr). The gaddr pointer will be updated with the last address + * for which data was written when returning to userspace. buff_user + * might be written to even if an error rc is returned. For instance + * if we encounter a fault after writing the first page of data. + * + * Context: kvm->lock needs to be held + * + * Return: + * 0 on success + * -ENOMEM if allocating the cache fails + * -EINVAL if gaddr is not aligned to 1MB + * -EINVAL if buff_user_len is not aligned to uv_info.conf_dump_storage_state_len + * -EINVAL if the UV call fails, rc and rrc will be set in this case + * -EFAULT if copying the result to buff_user failed + */ +int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user, + u64 *gaddr, u64 buff_user_len, u16 *rc, u16 *rrc) +{ + struct uv_cb_dump_stor_state uvcb = { + .header.cmd = UVC_CMD_DUMP_CONF_STOR_STATE, + .header.len = sizeof(uvcb), + .config_handle = kvm->arch.pv.handle, + .gaddr = *gaddr, + .dump_area_origin = 0, + }; + const u64 increment_len = uv_info.conf_dump_storage_state_len; + size_t buff_kvm_size; + size_t size_done = 0; + u8 *buff_kvm = NULL; + int cc, ret; + + ret = -EINVAL; + /* UV call processes 1MB guest storage chunks at a time */ + if (!IS_ALIGNED(*gaddr, HPAGE_SIZE)) + goto out; + + /* + * We provide the storage state for 1MB chunks of guest + * storage. The buffer will need to be aligned to + * conf_dump_storage_state_len so we don't end on a partial + * chunk. + */ + if (!buff_user_len || + !IS_ALIGNED(buff_user_len, increment_len)) + goto out; + + /* + * Allocate a buffer from which we will later copy to the user + * process. We don't want userspace to dictate our buffer size + * so we limit it to DUMP_BUFF_LEN. + */ + ret = -ENOMEM; + buff_kvm_size = min_t(u64, buff_user_len, DUMP_BUFF_LEN); + buff_kvm = vzalloc(buff_kvm_size); + if (!buff_kvm) + goto out; + + ret = 0; + uvcb.dump_area_origin = (u64)buff_kvm; + /* We will loop until the user buffer is filled or an error occurs */ + do { + /* Get 1MB worth of guest storage state data */ + cc = uv_call_sched(0, (u64)&uvcb); + + /* All or nothing */ + if (cc) { + ret = -EINVAL; + break; + } + + size_done += increment_len; + uvcb.dump_area_origin += increment_len; + buff_user_len -= increment_len; + uvcb.gaddr += HPAGE_SIZE; + + /* KVM Buffer full, time to copy to the process */ + if (!buff_user_len || size_done == DUMP_BUFF_LEN) { + if (copy_to_user(buff_user, buff_kvm, size_done)) { + ret = -EFAULT; + break; + } + + buff_user += size_done; + size_done = 0; + uvcb.dump_area_origin = (u64)buff_kvm; + } + } while (buff_user_len); + + /* Report back where we ended dumping */ + *gaddr = uvcb.gaddr; + + /* Lets only log errors, we don't want to spam */ +out: + if (ret) + KVM_UV_EVENT(kvm, 3, + "PROTVIRT DUMP STORAGE STATE: addr %llx ret %d, uvcb rc %x rrc %x", + uvcb.gaddr, ret, uvcb.header.rc, uvcb.header.rrc); + *rc = uvcb.header.rc; + *rrc = uvcb.header.rrc; + vfree(buff_kvm); + + return ret; +} + +/** + * kvm_s390_pv_dump_complete + * + * @kvm: pointer to the guest's KVM struct + * @buff_user: Userspace pointer where we will write the results to + * @rc: Pointer to where the uvcb return code is stored + * @rrc: Pointer to where the uvcb return reason code is stored + * + * Completes the dumping operation and writes the completion data to + * user space. + * + * Context: kvm->lock needs to be held + * + * Return: + * 0 on success + * -ENOMEM if allocating the completion buffer fails + * -EINVAL if the UV call fails, rc and rrc will be set in this case + * -EFAULT if copying the result to buff_user failed + */ +int kvm_s390_pv_dump_complete(struct kvm *kvm, void __user *buff_user, + u16 *rc, u16 *rrc) +{ + struct uv_cb_dump_complete complete = { + .header.len = sizeof(complete), + .header.cmd = UVC_CMD_DUMP_COMPLETE, + .config_handle = kvm_s390_pv_get_handle(kvm), + }; + u64 *compl_data; + int ret; + + /* Allocate dump area */ + compl_data = vzalloc(uv_info.conf_dump_finalize_len); + if (!compl_data) + return -ENOMEM; + complete.dump_area_origin = (u64)compl_data; + + ret = uv_call_sched(0, (u64)&complete); + *rc = complete.header.rc; + *rrc = complete.header.rrc; + KVM_UV_EVENT(kvm, 3, "PROTVIRT DUMP COMPLETE: rc %x rrc %x", + complete.header.rc, complete.header.rrc); + + if (!ret) { + /* + * kvm_s390_pv_dealloc_vm() will also (mem)set + * this to false on a reboot or other destroy + * operation for this vm. + */ + kvm->arch.pv.dumping = false; + kvm_s390_vcpu_unblock_all(kvm); + ret = copy_to_user(buff_user, compl_data, uv_info.conf_dump_finalize_len); + if (ret) + ret = -EFAULT; + } + vfree(compl_data); + /* If the UVC returned an error, translate it to -EINVAL */ + if (ret > 0) + ret = -EINVAL; + return ret; +} |