Date: Fri, 14 Jun 2024 17:50:35 +1000 From: Peter Grehan <grehan@freebsd.org> To: =?UTF-8?Q?Corvin_K=C3=B6hne?= <corvink@FreeBSD.org> Cc: virtualization@freebsd.org, Oleksandr Kryvulia <shuriku@shurik.kiev.ua> Subject: Re: bhyve passthru problem Message-ID: <c8c87fc3-2665-44c3-a8cf-6dcbd6525c38@freebsd.org> In-Reply-To: <38c9656c26fc3cee7ba733168c0fa2cdd01209d9.camel@FreeBSD.org> References: <a63589a8-2cb2-4952-83b1-7a97e2f8cd44@shurik.kiev.ua> <38c9656c26fc3cee7ba733168c0fa2cdd01209d9.camel@FreeBSD.org>
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> I don't know why bhyve validates the BAR size. The commit adding this > check is old [1] and doesn't explain it. What bhyve could do is > rounding up the BAR size to a full page size when allocating memory for > the BAR. > > [1] https://github.com/freebsd/freebsd- > src/commit/7a902ec0eccc752c9c38533ed123121eaaea1225 At the time, BIOSs would often place device BARs of less than a page size in the same physical page. Since EPT only gives page granularity, this would result in all those devices being available to the guest even if they hadn't been passed through. later, Peter.
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