[PATCH 3/8] KVM: SVM: refactor msr permission bitmap allocation

Maxim Levitsky
2020-08-20T09:13:58Z

Replace svm_vcpu_init_msrpm with svm_vcpu_alloc_msrpm, that also allocates
the msr bitmap and add svm_vcpu_free_msrpm to free it.

This will be used later to move the nested msr permission bitmap allocation
to nested.c

No functional change intended.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/svm/svm.c | 45 +++++++++++++++++++++---------------------
1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4338d2a2596e..e072ecace466 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -609,18 +609,29 @@ static void set_msr_interception(u32 *msrpm, unsigned msr,
msrpm[offset] = tmp;
}

-static void svm_vcpu_init_msrpm(u32 *msrpm)
+static u32 *svm_vcpu_alloc_msrpm(void)
{
int i;
+ u32 *msrpm;
+ struct page *pages = alloc_pages(GFP_KERNEL_ACCOUNT, MSRPM_ALLOC_ORDER);
+
+ if (!pages)
+ return NULL;

+ msrpm = page_address(pages);
memset(msrpm, 0xff, PAGE_SIZE * (1 << MSRPM_ALLOC_ORDER));

for (i = 0; direct_access_msrs[i].index != MSR_INVALID; i++) {
if (!direct_access_msrs[i].always)
continue;
-
set_msr_interception(msrpm, direct_access_msrs[i].index, 1, 1);
}
+ return msrpm;
+}
+
+static void svm_vcpu_free_msrpm(u32 *msrpm)
+{
+ __free_pages(virt_to_page(msrpm), MSRPM_ALLOC_ORDER);
}

static void add_msr_offset(u32 offset)
@@ -1172,9 +1183,7 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm;
struct page *vmcb_page;
- struct page *msrpm_pages;
struct page *hsave_page;
- struct page *nested_msrpm_pages;
int err;

BUILD_BUG_ON(offsetof(struct vcpu_svm, vcpu) != 0);
@@ -1185,21 +1194,13 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
if (!vmcb_page)
goto out;

- msrpm_pages = alloc_pages(GFP_KERNEL_ACCOUNT, MSRPM_ALLOC_ORDER);
- if (!msrpm_pages)
- goto free_page1;
-
- nested_msrpm_pages = alloc_pages(GFP_KERNEL_ACCOUNT, MSRPM_ALLOC_ORDER);
- if (!nested_msrpm_pages)
- goto free_page2;
-
hsave_page = alloc_page(GFP_KERNEL_ACCOUNT);
if (!hsave_page)
- goto free_page3;
+ goto free_page1;

err = avic_init_vcpu(svm);
if (err)
- goto free_page4;
+ goto free_page2;

/* We initialize this flag to true to make sure that the is_running
* bit would be set the first time the vcpu is loaded.
@@ -1210,11 +1211,13 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
svm->nested.hsave = page_address(hsave_page);
clear_page(svm->nested.hsave);

- svm->msrpm = page_address(msrpm_pages);
- svm_vcpu_init_msrpm(svm->msrpm);
+ svm->msrpm = svm_vcpu_alloc_msrpm();
+ if (!svm->msrpm)
+ goto free_page2;

- svm->nested.msrpm = page_address(nested_msrpm_pages);
- svm_vcpu_init_msrpm(svm->nested.msrpm);
+ svm->nested.msrpm = svm_vcpu_alloc_msrpm();
+ if (!svm->nested.msrpm)
+ goto free_page3;

svm->vmcb = page_address(vmcb_page);
clear_page(svm->vmcb);
@@ -1227,12 +1230,10 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)

return 0;

-free_page4:
- __free_page(hsave_page);
free_page3:
- __free_pages(nested_msrpm_pages, MSRPM_ALLOC_ORDER);
+ svm_vcpu_free_msrpm(svm->msrpm);
free_page2:
- __free_pages(msrpm_pages, MSRPM_ALLOC_ORDER);
+ __free_page(hsave_page);
free_page1:
__free_page(vmcb_page);
out:
--
2.26.2