svn commit: r273832 - in releng/10.1/sys/amd64: amd64 vmm
Neel Natu
neel at FreeBSD.org
Wed Oct 29 16:49:30 UTC 2014
Author: neel
Date: Wed Oct 29 16:49:28 2014
New Revision: 273832
URL: https://svnweb.freebsd.org/changeset/base/273832
Log:
MFS10 r273573, MFC r273356:
Fix a race in pmap_emulate_accessed_dirty() that could trigger a EPT
misconfiguration VM-exit.
MFS10 r273807, MFC r273666:
Don't pass the 'error' return from an I/O port handler directly to vm_run().
Approved by: re (kib)
Modified:
releng/10.1/sys/amd64/amd64/pmap.c
releng/10.1/sys/amd64/vmm/vmm_ioport.c
Directory Properties:
releng/10.1/ (props changed)
Modified: releng/10.1/sys/amd64/amd64/pmap.c
==============================================================================
--- releng/10.1/sys/amd64/amd64/pmap.c Wed Oct 29 16:48:18 2014 (r273831)
+++ releng/10.1/sys/amd64/amd64/pmap.c Wed Oct 29 16:49:28 2014 (r273832)
@@ -6787,9 +6787,19 @@ retry:
if (ftype == VM_PROT_WRITE) {
if ((*pte & PG_RW) == 0)
goto done;
- *pte |= PG_M;
+ /*
+ * Set the modified and accessed bits simultaneously.
+ *
+ * Intel EPT PTEs that do software emulation of A/D bits map
+ * PG_A and PG_M to EPT_PG_READ and EPT_PG_WRITE respectively.
+ * An EPT misconfiguration is triggered if the PTE is writable
+ * but not readable (WR=10). This is avoided by setting PG_A
+ * and PG_M simultaneously.
+ */
+ *pte |= PG_M | PG_A;
+ } else {
+ *pte |= PG_A;
}
- *pte |= PG_A;
/* try to promote the mapping */
if (va < VM_MAXUSER_ADDRESS)
Modified: releng/10.1/sys/amd64/vmm/vmm_ioport.c
==============================================================================
--- releng/10.1/sys/amd64/vmm/vmm_ioport.c Wed Oct 29 16:48:18 2014 (r273831)
+++ releng/10.1/sys/amd64/vmm/vmm_ioport.c Wed Oct 29 16:49:28 2014 (r273832)
@@ -106,15 +106,14 @@ emulate_inout_port(struct vm *vm, int vc
uint32_t mask, val;
int error;
- error = 0;
- *retu = true;
-
- if (vmexit->u.inout.port >= MAX_IOPORTS)
- goto done;
-
- handler = ioport_handler[vmexit->u.inout.port];
- if (handler == NULL)
- goto done;
+ /*
+ * If there is no handler for the I/O port then punt to userspace.
+ */
+ if (vmexit->u.inout.port >= MAX_IOPORTS ||
+ (handler = ioport_handler[vmexit->u.inout.port]) == NULL) {
+ *retu = true;
+ return (0);
+ }
mask = vie_size2mask(vmexit->u.inout.bytes);
@@ -124,20 +123,27 @@ emulate_inout_port(struct vm *vm, int vc
error = (*handler)(vm, vcpuid, vmexit->u.inout.in,
vmexit->u.inout.port, vmexit->u.inout.bytes, &val);
+ if (error) {
+ /*
+ * The value returned by this function is also the return value
+ * of vm_run(). This needs to be a positive number otherwise it
+ * can be interpreted as a "pseudo-error" like ERESTART.
+ *
+ * Enforce this by mapping all errors to EIO.
+ */
+ return (EIO);
+ }
- if (!error) {
- *retu = false;
- if (vmexit->u.inout.in) {
- vmexit->u.inout.eax &= ~mask;
- vmexit->u.inout.eax |= val & mask;
- error = vm_set_register(vm, vcpuid,
- VM_REG_GUEST_RAX, vmexit->u.inout.eax);
- KASSERT(error == 0, ("emulate_ioport: error %d "
- "setting guest rax register", error));
- }
+ if (vmexit->u.inout.in) {
+ vmexit->u.inout.eax &= ~mask;
+ vmexit->u.inout.eax |= val & mask;
+ error = vm_set_register(vm, vcpuid, VM_REG_GUEST_RAX,
+ vmexit->u.inout.eax);
+ KASSERT(error == 0, ("emulate_ioport: error %d setting guest "
+ "rax register", error));
}
-done:
- return (error);
+ *retu = false;
+ return (0);
}
static int
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