From patchwork Tue Nov 7 14:55:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Isaku Yamahata X-Patchwork-Id: 13448954 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6CDE031591 for ; Tue, 7 Nov 2023 14:58:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="nxhEzkxw" Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EB81D57; Tue, 7 Nov 2023 06:58:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1699369098; x=1730905098; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=az0Zf9XrHGdSnYQvBicS+yUZFO3/U2MPO+vM4+fc3KM=; b=nxhEzkxwivE7EMCSoj3kxgds+AlV8T7OeiKqS7yB3Zb5Jkf0wxtb3RjR s5bZraJ1CJdlpzWlxOQMcK3IBqQO2XRWPlTSIsqDye4Va+8yGcF79W5T7 RHFuHACEGHbuAUCiLNs/KvgYOAxOe09Sk1/0EyRfSP20Mx+AytycRCxdr n1OSG0K8AWwiARZl5kCDuEzlEKvcRpSl7DwQRlIQj+ykk9N9VdBqAWUIN QlRvUOyjxvgjG3fsGUAbmOzzLqH9+8cQ5iRWX/G1YAhWU6ZcnSuKKtVqe xCM35eCyjsBSDM4dwhiMv08uDA5PoHy/ULuBgv3kBuIordoLsx/Vp7Z9t A==; X-IronPort-AV: E=McAfee;i="6600,9927,10887"; a="2462203" X-IronPort-AV: E=Sophos;i="6.03,284,1694761200"; d="scan'208";a="2462203" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Nov 2023 06:58:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.03,284,1694761200"; d="scan'208";a="10851279" Received: from ls.sc.intel.com (HELO localhost) ([172.25.112.31]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Nov 2023 06:58:07 -0800 From: isaku.yamahata@intel.com To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com, Paolo Bonzini , erdemaktas@google.com, Sean Christopherson , Sagi Shahar , David Matlack , Kai Huang , Zhi Wang , chen.bo@intel.com, hang.yuan@intel.com, tina.zhang@intel.com Subject: [PATCH v17 031/116] KVM: Allow page-sized MMU caches to be initialized with custom 64-bit values Date: Tue, 7 Nov 2023 06:55:57 -0800 Message-Id: <302f6c591af7b2ca01e08286009e489491708af3.1699368322.git.isaku.yamahata@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Sean Christopherson Add support to MMU caches for initializing a page with a custom 64-bit value, e.g. to pre-fill an entire page table with non-zero PTE values. The functionality will be used by x86 to support Intel's TDX, which needs to set bit 63 in all non-present PTEs in order to prevent !PRESENT page faults from getting reflected into the guest (Intel's EPT Violation #VE architecture made the less than brilliant decision of having the per-PTE behavior be opt-out instead of opt-in). Signed-off-by: Sean Christopherson Signed-off-by: Isaku Yamahata --- include/linux/kvm_types.h | 1 + virt/kvm/kvm_main.c | 16 ++++++++++++++-- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h index 9d1f7835d8c1..60c8d5c9eab9 100644 --- a/include/linux/kvm_types.h +++ b/include/linux/kvm_types.h @@ -94,6 +94,7 @@ struct gfn_to_pfn_cache { struct kvm_mmu_memory_cache { gfp_t gfp_zero; gfp_t gfp_custom; + u64 init_value; struct kmem_cache *kmem_cache; int capacity; int nobjs; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 29fdb39976e0..7d9f4f9bb115 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -403,12 +403,17 @@ static void kvm_flush_shadow_all(struct kvm *kvm) static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc, gfp_t gfp_flags) { + void *page; + gfp_flags |= mc->gfp_zero; if (mc->kmem_cache) return kmem_cache_alloc(mc->kmem_cache, gfp_flags); - else - return (void *)__get_free_page(gfp_flags); + + page = (void *)__get_free_page(gfp_flags); + if (page && mc->init_value) + memset64(page, mc->init_value, PAGE_SIZE / sizeof(mc->init_value)); + return page; } int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int capacity, int min) @@ -423,6 +428,13 @@ int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int capacity, if (WARN_ON_ONCE(!capacity)) return -EIO; + /* + * Custom init values can be used only for page allocations, + * and obviously conflict with __GFP_ZERO. + */ + if (WARN_ON_ONCE(mc->init_value && (mc->kmem_cache || mc->gfp_zero))) + return -EIO; + mc->objects = kvmalloc_array(sizeof(void *), capacity, gfp); if (!mc->objects) return -ENOMEM;