From dbcc4fba01bbdacf29e632c800a2c3e6bda0cd98 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 26 Jun 2024 14:10:40 +0200 Subject: [PATCH] x86/EPT: drop questionable mfn_valid() from epte_get_entry_emt() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit mfn_valid() is RAM-focused; it will often return false for MMIO. Yet access to actual MMIO space should not generally be restricted to UC only; especially video frame buffer accesses are unduly affected by such a restriction. Since, as of 777c71d31325 ("x86/EPT: avoid marking non-present entries for re-configuring"), the function won't be called with INVALID_MFN or, worse, truncated forms thereof anymore, we call fully drop that check. Fixes: 81fd0d3ca4b2 ("x86/hvm: simplify 'mmio_direct' check in epte_get_entry_emt()") Signed-off-by: Jan Beulich Reviewed-by: Roger Pau Monné master commit: 4fdd8d75566fdad06667a79ec0ce6f43cc466c54 master date: 2024-06-13 16:55:22 +0200 --- xen/arch/x86/mm/p2m-ept.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c index b7d7a5b68c..57fc1d352c 100644 --- a/xen/arch/x86/mm/p2m-ept.c +++ b/xen/arch/x86/mm/p2m-ept.c @@ -512,12 +512,6 @@ int epte_get_entry_emt(struct domain *d, gfn_t gfn, mfn_t mfn, return -1; } - if ( !mfn_valid(mfn) ) - { - *ipat = true; - return MTRR_TYPE_UNCACHABLE; - } - /* * Conditional must be kept in sync with the code in * {iomem,ioports}_{permit,deny}_access(). -- 2.39.5