kvm: remove non-sane sanity check

Apparently some platforms don't have pSize < vSize.

Fixes #208

PiperOrigin-RevId: 245480998
Change-Id: I2a98229912f4ccbfcd8e79dfa355104f14275a9c

1 files changed, 8 insertions, 7 deletions

diff --git a/pkg/sentry/platform/kvm/physical_map.go b/pkg/sentry/platform/kvm/physical_map.go
index b908cae6a..9d7dca5b3 100644
--- a/pkg/sentry/platform/kvm/physical_map.go
+++ b/pkg/sentry/platform/kvm/physical_map.go
@@ -50,8 +50,9 @@ type physicalRegion struct {
 var physicalRegions []physicalRegion
 
 // fillAddressSpace fills the host address space with PROT_NONE mappings until
-// the number of available bits until we have a host address space size that is
-// equal to the physical address space.
+// we have a host address space size that is less than or equal to the physical
+// address space. This allows us to have an injective host virtual to guest
+// physical mapping.
 //
 // The excluded regions are returned.
 func fillAddressSpace() (excludedRegions []region) {
@@ -67,11 +68,6 @@ func fillAddressSpace() (excludedRegions []region) {
 	pSize := uintptr(1) << ring0.PhysicalAddressBits()
 	pSize -= reservedMemory
 
-	// Sanity check.
-	if vSize < pSize {
-		panic(fmt.Sprintf("vSize (%x) < pSize (%x)", vSize, pSize))
-	}
-
 	// Add specifically excluded regions; see excludeVirtualRegion.
 	applyVirtualRegions(func(vr virtualRegion) {
 		if excludeVirtualRegion(vr) {
@@ -81,6 +77,11 @@ func fillAddressSpace() (excludedRegions []region) {
 		}
 	})
 
+	// Do we need any more work?
+	if vSize < pSize {
+		return excludedRegions
+	}
+
 	// Calculate the required space and fill it.
 	//
 	// Note carefully that we add faultBlockSize to required up front, and