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keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: <1788509352.8631fc262581453bbf619ec5b2062170.1a06b76f0aa000c4f3@vates.tech> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-purgate-ID: tlsNG-bad1c0/1788510281-3A0C5034-1613B71D/0/0 X-purgate-type: clean X-purgate-size: 2934 On 04.09.2026 10:09, Anthony PERARD wrote: > On Tue, Aug 18, 2026 at 04:08:04PM +0200, Jan Beulich wrote: >> On 20.04.2026 11:38, Julian Vetter wrote: >>> Julian Vetter (3): >>> ioreq: switch ioreq page allocation to vmap >>> ioreq: Indent ioreq_server_alloc_mfn() body one level deeper >>> x86/ioreq: Extend ioreq server to support multiple ioreq pages >>> >>> xen/arch/x86/hvm/ioreq.c | 63 ++++++++++++++++--- >>> xen/common/ioreq.c | 127 ++++++++++++++++++++++++++------------- >>> xen/include/xen/ioreq.h | 13 +++- >>> 3 files changed, 151 insertions(+), 52 deletions(-) >> >> For (future) reference, in case it wasn't said earlier: >> >> To be able to test this, at least the last patch here will want to wait >> until the apic_id == vcpu_id * 2 issue was addressed. Andrew said he'd pick >> up Alejandro's work there, thus - once finished - permitting up to 255 >> vCPU-s (i.e. requiring 2 IOREQ pages). >> >> Once (really: before) we grow the number of vCPU-s for HVM, we need to >> revisit the amount of VA space set aside for vmap(). For many years we've >> been adding new uses of vmap() without making sure its reserved range is >> still adequately sized. >> >> Since multi-page functionality added here will also need qemu changes, and >> since we did determine (elsewhere) that ioreq_t needs to grow as well, it >> remains to be decided whether the two changes wouldn't better be done >> together, to keep the qemu backwards compatibility logic somewhat limited >> in size / complexity. Anthony (in particular) - thoughts? > > Put like that, how can I say "no" to merge both changes together :-) > > It will certainly be simpler to maintain if having one feature mean also > having the other. But it kind of depends on whether both changes are > ready to go in at around the same time. I don't really know how the > changes in QEMU will look like, and how QEMU will choose or have a > choice of which feature to use, and it might be one that can be > negotiated as runtime and the other one been a compile time change (as I > think QEMU still depends on unstable ABI). > > But it looks like both changes in QEMU are for having more vCPU, so > having both at the same time might be better. Growing ioreq_t (in particular the data size it can hold) doesn't have anything to do with increased vCPU count, I think. > So yes, I'm all for less complexity, but I can't ask for this to be a > blocker, especially if the other change might takes years. So far, I > don't think I've seen any patches for QEMU. How exactly a new ioreq_t would want to look like remains to be discussed. Perhaps we could go an intermediate route here: Add provisions (e.g. a full page per vCPU, plus a format identifier at the start of that page), allowing the enlarged ioreq_t to be put on top, yet without needing any (further) changes to the map/unmap logic? Jan