Author: avg
Date: Tue Jan 9 14:22:18 2018
New Revision: 327726
URL: https://svnweb.freebsd.org/changeset/base/327726
Log:
vmm/svm: contigmalloc of the whole svm_softc is excessive
This is a followup to r307903.
struct svm_softc takes more than 200 kilobytes while what we really need
is 3 contiguous pages for I/O permission map and 2 contiguous pages for
MSR permission map. Other physically mapped structures have a size of
a single page, so a proper alignment is sufficient for their correct
mapping.
Thus, only the permission maps are allocated with contigmalloc now,
the softc is allocated with a regular malloc.
Additionally, this commit adds a check that malloc returns memory with the
expected page alignment and that contigmalloc does not fail.
Unfortunately, at present svm_vminit() is expected to always succeed and
there is no way to report an error.
So, a contigmalloc failure leads to a panic.
We should probably fix this.
MFC after: 2 weeks
Modified:
head/sys/amd64/vmm/amd/svm.c
head/sys/amd64/vmm/amd/svm_softc.h
Modified: head/sys/amd64/vmm/amd/svm.c
==============================================================================
--- head/sys/amd64/vmm/amd/svm.c Tue Jan 9 13:43:04 2018
(r327725)
+++ head/sys/amd64/vmm/amd/svm.c Tue Jan 9 14:22:18 2018
(r327726)
@@ -517,15 +517,26 @@ svm_vminit(struct vm *vm, pmap_t pmap)
vm_paddr_t msrpm_pa, iopm_pa, pml4_pa;
int i;
- svm_sc = contigmalloc(sizeof (*svm_sc), M_SVM, M_WAITOK | M_ZERO,
- 0, ~(vm_paddr_t)0, PAGE_SIZE, 0);
+ svm_sc = malloc(sizeof (*svm_sc), M_SVM, M_WAITOK | M_ZERO);
+ if (((uintptr_t)svm_sc & PAGE_MASK) != 0)
+ panic("malloc of svm_softc not aligned on page boundary");
+
+ svm_sc->msr_bitmap = contigmalloc(SVM_MSR_BITMAP_SIZE, M_SVM,
+ M_WAITOK, 0, ~(vm_paddr_t)0, PAGE_SIZE, 0);
+ if (svm_sc->msr_bitmap == NULL)
+ panic("contigmalloc of SVM MSR bitmap failed");
+ svm_sc->iopm_bitmap = contigmalloc(SVM_IO_BITMAP_SIZE, M_SVM,
+ M_WAITOK, 0, ~(vm_paddr_t)0, PAGE_SIZE, 0);
+ if (svm_sc->iopm_bitmap == NULL)
+ panic("contigmalloc of SVM IO bitmap failed");
+
svm_sc->vm = vm;
svm_sc->nptp = (vm_offset_t)vtophys(pmap->pm_pml4);
/*
* Intercept read and write accesses to all MSRs.
*/
- memset(svm_sc->msr_bitmap, 0xFF, sizeof(svm_sc->msr_bitmap));
+ memset(svm_sc->msr_bitmap, 0xFF, SVM_MSR_BITMAP_SIZE);
/*
* Access to the following MSRs is redirected to the VMCB when the
@@ -553,7 +564,7 @@ svm_vminit(struct vm *vm, pmap_t pmap)
svm_msr_rd_ok(svm_sc->msr_bitmap, MSR_EFER);
/* Intercept access to all I/O ports. */
- memset(svm_sc->iopm_bitmap, 0xFF, sizeof(svm_sc->iopm_bitmap));
+ memset(svm_sc->iopm_bitmap, 0xFF, SVM_IO_BITMAP_SIZE);
iopm_pa = vtophys(svm_sc->iopm_bitmap);
msrpm_pa = vtophys(svm_sc->msr_bitmap);
@@ -2043,7 +2054,9 @@ svm_vmcleanup(void *arg)
{
struct svm_softc *sc = arg;
- contigfree(sc, sizeof (*sc), M_SVM);
+ contigfree(sc->iopm_bitmap, SVM_IO_BITMAP_SIZE, M_SVM);
+ contigfree(sc->msr_bitmap, SVM_MSR_BITMAP_SIZE, M_SVM);
+ free(sc, M_SVM);
}
static register_t *
Modified: head/sys/amd64/vmm/amd/svm_softc.h
==============================================================================
--- head/sys/amd64/vmm/amd/svm_softc.h Tue Jan 9 13:43:04 2018
(r327725)
+++ head/sys/amd64/vmm/amd/svm_softc.h Tue Jan 9 14:22:18 2018
(r327726)
@@ -56,13 +56,13 @@ struct svm_vcpu {
* SVM softc, one per virtual machine.
*/
struct svm_softc {
- uint8_t iopm_bitmap[SVM_IO_BITMAP_SIZE]; /* shared by all vcpus */
- uint8_t msr_bitmap[SVM_MSR_BITMAP_SIZE]; /* shared by all vcpus */
uint8_t apic_page[VM_MAXCPU][PAGE_SIZE];
struct svm_vcpu vcpu[VM_MAXCPU];
vm_offset_t nptp; /* nested page table */
+ uint8_t *iopm_bitmap; /* shared by all vcpus */
+ uint8_t *msr_bitmap; /* shared by all vcpus */
struct vm *vm;
-} __aligned(PAGE_SIZE);
+};
CTASSERT((offsetof(struct svm_softc, nptp) & PAGE_MASK) == 0);
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