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Fri, 10 Jul 2020 08:41:33 +0000 (UTC) Subject: Re: [PATCH RFC 2/5] s390x: implement diag260 From: David Hildenbrand To: Cornelia Huck References: <20200708185135.46694-1-david@redhat.com> <20200708185135.46694-3-david@redhat.com> <20200709123741.28a1e3b2.cohuck@redhat.com> <520dafce-917f-9a88-a3ee-c7d614ac113f@redhat.com> Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: Date: Fri, 10 Jul 2020 10:41:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <520dafce-917f-9a88-a3ee-c7d614ac113f@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=david@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/10 00:36:21 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Huth , Janosch Frank , "Michael S . Tsirkin" , Heiko Carstens , qemu-devel@nongnu.org, Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org, Claudio Imbrenda , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10.07.20 10:32, David Hildenbrand wrote: > On 09.07.20 12:37, Cornelia Huck wrote: >> On Wed, 8 Jul 2020 20:51:32 +0200 >> David Hildenbrand wrote: >> >>> Let's implement the "storage configuration" part of diag260. This diag >>> is found under z/VM, to indicate usable chunks of memory tot he guest OS. >>> As I don't have access to documentation, I have no clue what the actual >>> error cases are, and which other stuff we could eventually query using this >>> interface. Somebody with access to documentation should fix this. This >>> implementation seems to work with Linux guests just fine. >>> >>> The Linux kernel supports diag260 to query the available memory since >>> v4.20. Older kernels / kvm-unit-tests will later fail to run in such a VM >>> (with maxmem being defined and bigger than the memory size, e.g., "-m >>> 2G,maxmem=4G"), just as if support for SCLP storage information is not >>> implemented. They will fail to detect the actual initial memory size. >>> >>> This interface allows us to expose the maximum ramsize via sclp >>> and the initial ramsize via diag260 - without having to mess with the >>> memory increment size and having to align the initial memory size to it. >>> >>> This is a preparation for memory device support. We'll unlock the >>> implementation with a new QEMU machine that supports memory devices. >>> >>> Signed-off-by: David Hildenbrand >>> --- >>> target/s390x/diag.c | 57 ++++++++++++++++++++++++++++++++++++++ >>> target/s390x/internal.h | 2 ++ >>> target/s390x/kvm.c | 11 ++++++++ >>> target/s390x/misc_helper.c | 6 ++++ >>> target/s390x/translate.c | 4 +++ >>> 5 files changed, 80 insertions(+) >>> >>> diff --git a/target/s390x/diag.c b/target/s390x/diag.c >>> index 1a48429564..c3b1e24b2c 100644 >>> --- a/target/s390x/diag.c >>> +++ b/target/s390x/diag.c >>> @@ -23,6 +23,63 @@ >>> #include "hw/s390x/pv.h" >>> #include "kvm_s390x.h" >>> >>> +void handle_diag_260(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra) >>> +{ >>> + MachineState *ms = MACHINE(qdev_get_machine()); >>> + const ram_addr_t initial_ram_size = ms->ram_size; >>> + const uint64_t subcode = env->regs[r3]; >>> + S390CPU *cpu = env_archcpu(env); >>> + ram_addr_t addr, length; >>> + uint64_t tmp; >>> + >>> + /* TODO: Unlock with new QEMU machine. */ >>> + if (false) { >>> + s390_program_interrupt(env, PGM_OPERATION, ra); >>> + return; >>> + } >>> + >>> + /* >>> + * There also seems to be subcode "0xc", which stores the size of the >>> + * first chunk and the total size to r1/r2. It's only used by very old >>> + * Linux, so don't implement it. >> >> FWIW, >> https://www-01.ibm.com/servers/resourcelink/svc0302a.nsf/pages/zVMV7R1sc246272/$file/hcpb4_v7r1.pdf >> seems to list the available subcodes. Anything but 0xc and 0x10 is for >> 24/31 bit only, so we can safely ignore them. Not sure what we want to >> do with 0xc: it is supposed to "Return the highest addressable byte of >> virtual storage in the host-primary address space, including named >> saved systems and saved segments", so returning the end of the address >> space should be easy enough, but not very useful. >> >>> + */ >>> + if ((r1 & 1) || subcode != 0x10) { >>> + s390_program_interrupt(env, PGM_SPECIFICATION, ra); >>> + return; >>> + } >>> + addr = env->regs[r1]; >>> + length = env->regs[r1 + 1]; >>> + >>> + /* FIXME: Somebody with documentation should fix this. */ >> >> Doc mentioned above says for specification exception: >> >> "For subcode X'10': >> • Rx is not an even-numbered register. >> • The address contained in Rx is not on a quadword boundary. >> • The length contained in Rx+1 is not a positive multiple of 16." >> >>> + if (!QEMU_IS_ALIGNED(addr, 16) || !QEMU_IS_ALIGNED(length, 16)) { >>> + s390_program_interrupt(env, PGM_SPECIFICATION, ra); >>> + return; >>> + } >>> + >>> + /* FIXME: Somebody with documentation should fix this. */ >>> + if (!length) { >> >> Probably specification exception as well? >> >>> + setcc(cpu, 3); >>> + return; >>> + } >>> + >>> + /* FIXME: Somebody with documentation should fix this. */ >> >> For access exception: >> >> "For subcode X'10', an error occurred trying to store the extent >> information into the guest's output area." >> >>> + if (!address_space_access_valid(&address_space_memory, addr, length, true, >>> + MEMTXATTRS_UNSPECIFIED)) { >>> + s390_program_interrupt(env, PGM_ADDRESSING, ra); >>> + return; >>> + } >>> + >>> + /* Indicate our initial memory ([0 .. ram_size - 1]) */ >>> + tmp = cpu_to_be64(0); >>> + cpu_physical_memory_write(addr, &tmp, sizeof(tmp)); >>> + tmp = cpu_to_be64(initial_ram_size - 1); >>> + cpu_physical_memory_write(addr + sizeof(tmp), &tmp, sizeof(tmp)); >>> + >>> + /* Exactly one entry was stored. */ >>> + env->regs[r3] = 1; >>> + setcc(cpu, 0); >>> +} >>> + >>> int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3) >>> { >>> uint64_t func = env->regs[r1]; >> >> (...) >> >>> diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c >>> index 58dbc023eb..d7274eb320 100644 >>> --- a/target/s390x/misc_helper.c >>> +++ b/target/s390x/misc_helper.c >>> @@ -116,6 +116,12 @@ void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num) >>> uint64_t r; >>> >>> switch (num) { >>> + case 0x260: >>> + qemu_mutex_lock_iothread(); >>> + handle_diag_260(env, r1, r3, GETPC()); >>> + qemu_mutex_unlock_iothread(); >>> + r = 0; >>> + break; >>> case 0x500: >>> /* KVM hypercall */ >>> qemu_mutex_lock_iothread(); >> >> Looking at the doc referenced above, it seems that we treat every diag >> call as privileged under tcg; but it seems that 0x44 isn't? (Unrelated >> to your patch; maybe I'm misreading.) > > That's also a BUG in kvm then? > > int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) > { > ... > if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) > return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); > ... > } > But OTOH, it does not sound sane if user space can bypass the OS to yield the CPU ... so this might just be a wrong documentation. All DIAGs should be privileged IIRC. -- Thanks, David / dhildenb