# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1221040389 -3600
# Node ID 6a37b3d966f90f3c1604c9a3045d033cc5eeb4ea
# Parent b5912430e66c900c2092c035227816f43f7caeb0
vtd: Add a command line param to enable/disable pass-through feature
Taking security into accout, it's not suitable to bypass VT-d
translation for Dom0 by default when the pass-through field in
extended capability register is set. This feature is for people/usages
who are not overly worried about security/isolation, but want better
performance.
This patch adds a command line param that controls if it's enabled or
disabled.
Signed-off-by: Weidong Han <weidong.han@xxxxxxxxx>
---
xen/drivers/passthrough/iommu.c | 4 ++++
xen/drivers/passthrough/vtd/iommu.c | 9 ++++++---
xen/include/xen/iommu.h | 1 +
3 files changed, 11 insertions(+), 3 deletions(-)
diff -r b5912430e66c -r 6a37b3d966f9 xen/drivers/passthrough/iommu.c
--- a/xen/drivers/passthrough/iommu.c Wed Sep 10 10:51:48 2008 +0100
+++ b/xen/drivers/passthrough/iommu.c Wed Sep 10 10:53:09 2008 +0100
@@ -33,11 +33,13 @@ int amd_iov_detect(void);
* pv Enable IOMMU for PV domains
* no-pv Disable IOMMU for PV domains (default)
* force|required Don't boot unless IOMMU is enabled
+ * passthrough Bypass VT-d translation for Dom0
*/
custom_param("iommu", parse_iommu_param);
int iommu_enabled = 0;
int iommu_pv_enabled = 0;
int force_iommu = 0;
+int iommu_passthrough = 0;
static void __init parse_iommu_param(char *s)
{
@@ -58,6 +60,8 @@ static void __init parse_iommu_param(cha
iommu_pv_enabled = 0;
else if ( !strcmp(s, "force") || !strcmp(s, "required") )
force_iommu = 1;
+ else if ( !strcmp(s, "passthrough") )
+ iommu_passthrough = 1;
s = ss + 1;
} while ( ss );
diff -r b5912430e66c -r 6a37b3d966f9 xen/drivers/passthrough/vtd/iommu.c
--- a/xen/drivers/passthrough/vtd/iommu.c Wed Sep 10 10:51:48 2008 +0100
+++ b/xen/drivers/passthrough/vtd/iommu.c Wed Sep 10 10:53:09 2008 +0100
@@ -1090,7 +1090,8 @@ static int domain_context_mapping_one(
}
spin_lock_irqsave(&iommu->lock, flags);
- if ( ecap_pass_thru(iommu->ecap) && (domain->domain_id == 0) )
+ if ( iommu_passthrough &&
+ ecap_pass_thru(iommu->ecap) && (domain->domain_id == 0) )
{
context_set_translation_type(*context, CONTEXT_TT_PASS_THRU);
agaw = level_to_agaw(iommu->nr_pt_levels);
@@ -1463,7 +1464,8 @@ int intel_iommu_map_page(
iommu = drhd->iommu;
/* do nothing if dom0 and iommu supports pass thru */
- if ( ecap_pass_thru(iommu->ecap) && (d->domain_id == 0) )
+ if ( iommu_passthrough &&
+ ecap_pass_thru(iommu->ecap) && (d->domain_id == 0) )
return 0;
pg_maddr = addr_to_dma_page_maddr(d, (paddr_t)gfn << PAGE_SHIFT_4K, 1);
@@ -1502,7 +1504,8 @@ int intel_iommu_unmap_page(struct domain
iommu = drhd->iommu;
/* do nothing if dom0 and iommu supports pass thru */
- if ( ecap_pass_thru(iommu->ecap) && (d->domain_id == 0) )
+ if ( iommu_passthrough &&
+ ecap_pass_thru(iommu->ecap) && (d->domain_id == 0) )
return 0;
dma_pte_clear_one(d, (paddr_t)gfn << PAGE_SHIFT_4K);
diff -r b5912430e66c -r 6a37b3d966f9 xen/include/xen/iommu.h
--- a/xen/include/xen/iommu.h Wed Sep 10 10:51:48 2008 +0100
+++ b/xen/include/xen/iommu.h Wed Sep 10 10:53:09 2008 +0100
@@ -31,6 +31,7 @@ extern int iommu_enabled;
extern int iommu_enabled;
extern int iommu_pv_enabled;
extern int force_iommu;
+extern int iommu_passthrough;
#define domain_hvm_iommu(d) (&d->arch.hvm_domain.hvm_iommu)
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