From: Alistair Francis <alistair.francis@wdc.com>
To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: alistair23@gmail.com, palmer@sifive.com, alistair.francis@wdc.com
Subject: [Qemu-devel] [PATCH-4.2 v1 1/6] target/riscv: Don't set write permissions on dirty PTEs
Date: Thu, 25 Jul 2019 11:52:01 -0700 [thread overview]
Message-ID: <6a7d3b524e7c0a41ef232d9dc21d7c337b05b97d.1564080680.git.alistair.francis@wdc.com> (raw)
In-Reply-To: <cover.1564080680.git.alistair.francis@wdc.com>
Setting write permission on dirty PTEs results in userspace inside a
Hypervisor guest (VU) becoming corrupted. This appears to be becuase it
ends up with write permission in the second stage translation in cases
where we aren't doing a store.
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
target/riscv/cpu_helper.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index e32b6126af..f027be7f16 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -340,10 +340,8 @@ restart:
if ((pte & PTE_X)) {
*prot |= PAGE_EXEC;
}
- /* add write permission on stores or if the page is already dirty,
- so that we TLB miss on later writes to update the dirty bit */
- if ((pte & PTE_W) &&
- (access_type == MMU_DATA_STORE || (pte & PTE_D))) {
+ /* add write permission on stores */
+ if ((pte & PTE_W) && (access_type == MMU_DATA_STORE)) {
*prot |= PAGE_WRITE;
}
return TRANSLATE_SUCCESS;
--
2.22.0
next prev parent reply other threads:[~2019-07-25 18:55 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 18:51 [Qemu-devel] [PATCH-4.2 v1 0/6] RISC-V: Hypervisor prep work part 2 Alistair Francis
2019-07-25 18:52 ` Alistair Francis [this message]
2019-07-29 14:33 ` [Qemu-devel] [PATCH-4.2 v1 1/6] target/riscv: Don't set write permissions on dirty PTEs Philippe Mathieu-Daudé
2019-07-25 18:52 ` [Qemu-devel] [PATCH-4.2 v1 2/6] target/riscv: Remove strict perm checking for CSR R/W Alistair Francis
2019-07-25 21:47 ` [Qemu-devel] [Qemu-riscv] " Jonathan Behrens
2019-07-26 20:24 ` Alistair Francis
2019-07-26 21:00 ` Jonathan Behrens
2019-07-26 22:28 ` Alistair Francis
2019-07-25 18:52 ` [Qemu-devel] [PATCH-4.2 v1 3/6] riscv: plic: Remove unused interrupt functions Alistair Francis
2019-07-26 15:22 ` [Qemu-devel] [Qemu-riscv] " Jonathan Behrens
2019-07-29 14:28 ` [Qemu-devel] " Philippe Mathieu-Daudé
2019-07-29 17:32 ` Chih-Min Chao
2019-07-25 18:52 ` [Qemu-devel] [PATCH-4.2 v1 4/6] target/riscv: Create function to test if FP is enabled Alistair Francis
2019-07-29 14:31 ` Philippe Mathieu-Daudé
2019-07-29 16:56 ` [Qemu-devel] [Qemu-riscv] " Chih-Min Chao
2019-07-30 18:32 ` Alistair Francis
2019-07-30 8:49 ` [Qemu-devel] " Christophe de Dinechin
2019-07-30 18:33 ` Alistair Francis
2019-07-25 18:52 ` [Qemu-devel] [PATCH-4.2 v1 5/6] target/riscv: Update the Hypervisor CSRs to v0.4 Alistair Francis
2019-07-26 17:40 ` Chih-Min Chao
2019-07-26 20:20 ` Alistair Francis
2019-07-25 18:52 ` [Qemu-devel] [PATCH-4.2 v1 6/6] target/riscv: Fix Floating Point register names Alistair Francis
2019-07-29 15:19 ` Chih-Min Chao
2019-07-30 18:37 ` Alistair Francis
2019-07-31 8:10 ` Chih-Min Chao
2019-08-05 17:49 ` Alistair Francis
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