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Wed, 14 Feb 2024 03:38:15 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCViaO4MGoPO7IZg5plLx5X+U3+toIuqfG1lYuuzj9CUD77LaktBSUtvzhgRLsb5l2NYWUZcjum4gPNPdHEq9hLtZmAdaclXTVYwc64NTXsnjv4sD14/DFjaNchspjRwmo+LmrOnqf8mP49F3/Ua3462HYq8l97ccNp/EgYGQ8LlnrlPHn1+bOXImcUITlcBryu+f5VpD+KNjfq8Awfkpw+u0i9bYCu/WOUy26nNLd5iR0kLimcbIAwuDq29nwEPeP4Hu07mfhrRPq77YVhIJuPi+gAJCX6QYr2/yZop521Cgw5ooA/Wte69ZDq9VFTe8juiPO8wUcpXNIfDBAllj0CDyGmmKrZn5nU3rKcoXlq7Z8clbIJjIzAckTmCxxKgDwCEYEIMjA== Message-ID: <123f4cc2-8fc7-4e2a-b44c-78a81b3a1a3e@suse.com> Date: Wed, 14 Feb 2024 12:38:13 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v13 01/14] vpci: use per-domain PCI lock to protect vpci structure Content-Language: en-US To: Stewart Hildebrand , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= Cc: Oleksandr Andrushchenko , Andrew Cooper , Wei Liu , George Dunlap , Julien Grall , Stefano Stabellini , Jun Nakajima , Kevin Tian , Paul Durrant , Volodymyr Babchuk , xen-devel@lists.xenproject.org References: <20240202213321.1920347-1-stewart.hildebrand@amd.com> <20240202213321.1920347-2-stewart.hildebrand@amd.com> From: Jan Beulich Autocrypt: addr=jbeulich@suse.com; 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: <20240202213321.1920347-2-stewart.hildebrand@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 02.02.2024 22:33, Stewart Hildebrand wrote: > --- a/xen/arch/x86/physdev.c > +++ b/xen/arch/x86/physdev.c > @@ -123,7 +123,9 @@ int physdev_map_pirq(domid_t domid, int type, int *index, int *pirq_p, > > case MAP_PIRQ_TYPE_MSI: > case MAP_PIRQ_TYPE_MULTI_MSI: > + pcidevs_lock(); > ret = allocate_and_map_msi_pirq(d, *index, pirq_p, type, msi); > + pcidevs_unlock(); > break; I'm afraid I need to come back to this: This is the only place where this patch retains (moves) use of the global lock. By moving, its scope is actually extended. It was previously said that conversion doesn't happen to limit the scope of what is changing. But with allocate_and_map_msi_pirq() being happy about either lock being held, I'm having a hard time seeing why here the global lock would continue to need using. To me doing so suggests uncertainty whether the checking in the function is actually correct. Jan