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From: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>
To: linux-kernel@vger.kernel.org
Cc: pv-drivers@vmware.com, linux-graphics-maintainer@vmware.com,
	x86@kernel.org, "Thomas Hellstrom" <thellstrom@vmware.com>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Christoph Hellwig" <hch@infradead.org>,
	"Christian König" <christian.koenig@amd.com>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	"Tom Lendacky" <thomas.lendacky@amd.com>
Subject: [PATCH 2/2] dma-mapping: Fix dma_pgprot() for unencrypted coherent pages
Date: Tue, 10 Sep 2019 15:35:42 +0200	[thread overview]
Message-ID: <20190910133542.64523-3-thomas_os@shipmail.org> (raw)
In-Reply-To: <20190910133542.64523-1-thomas_os@shipmail.org>

From: Thomas Hellstrom <thellstrom@vmware.com>

When force_dma_unencrypted() returns true, the linear kernel map of the
coherent pages have had the encryption bit explicitly cleared and the
page content is unencrypted. Make sure that any additional PTEs we set
up to these pages also have the encryption bit cleared by having
dma_pgprot() return a protection with the encryption bit cleared in this
case.

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
---
 kernel/dma/mapping.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index b0038ca3aa92..2b499dcae74f 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -157,6 +157,8 @@ EXPORT_SYMBOL(dma_get_sgtable_attrs);
  */
 pgprot_t dma_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs)
 {
+	if (force_dma_unencrypted(dev))
+		prot = pgprot_decrypted(prot);
 	if (dev_is_dma_coherent(dev) ||
 	    (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) &&
              (attrs & DMA_ATTR_NON_CONSISTENT)))
-- 
2.20.1


  parent reply	other threads:[~2019-09-10 13:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-10 13:35 [PATCH 0/2] Fix SEV user-space mapping of unencrypted coherent memory Thomas Hellström (VMware)
2019-09-10 13:35 ` [PATCH 1/2] x86: Don't let pgprot_modify() change the page encryption bit Thomas Hellström (VMware)
2019-09-10 13:35 ` Thomas Hellström (VMware) [this message]
2019-09-11  5:59 ` [PATCH 0/2] Fix SEV user-space mapping of unencrypted coherent memory Ingo Molnar
2019-09-11  8:07   ` Thomas Hellström (VMware)

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