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KVM: nSVM: Merge MSRPM in 64-bit chunks on 64-bit kernels

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When merging L0 and L1 MSRPMs as part of nested VMRUN emulation, access
the bitmaps using "unsigned long" chunks, i.e. use 8-byte access for
64-bit kernels instead of arbitrarily working on 4-byte chunks.

Opportunistically rename local variables in nested_svm_merge_msrpm() to
more precisely/accurately reflect their purpose ("offset" in particular is
extremely ambiguous).

Link: https://lore.kernel.org/r/20250610225737.156318-30-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2025-06-10 15:57:34 -07:00
parent 5904ba5172
commit 54f1c77061
1 changed files with 11 additions and 10 deletions
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21
arch/x86/kvm/svm/nested.c
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@ -196,6 +196,7 @@ void recalc_intercepts(struct vcpu_svm *svm)
*/
static int nested_svm_msrpm_merge_offsets[6] __ro_after_init;
static int nested_svm_nr_msrpm_merge_offsets __ro_after_init;
typedef unsigned long nsvm_msrpm_merge_t;
int __init nested_svm_init_msrpm_merge_offsets(void)
{
@ -230,10 +231,10 @@ int __init nested_svm_init_msrpm_merge_offsets(void)
return -EIO;
/*
* Merging is done in 32-bit chunks to reduce the number of
* accesses to L1's bitmap.
* Merging is done in chunks to reduce the number of accesses
* to L1's bitmap.
*/
offset = bit_nr / BITS_PER_BYTE / sizeof(u32);
offset = bit_nr / BITS_PER_BYTE / sizeof(nsvm_msrpm_merge_t);
for (j = 0; j < nested_svm_nr_msrpm_merge_offsets; j++) {
if (nested_svm_msrpm_merge_offsets[j] == offset)
@ -261,8 +262,8 @@ int __init nested_svm_init_msrpm_merge_offsets(void)
static bool nested_svm_merge_msrpm(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
u32 *msrpm02 = svm->nested.msrpm;
u32 *msrpm01 = svm->msrpm;
nsvm_msrpm_merge_t *msrpm02 = svm->nested.msrpm;
nsvm_msrpm_merge_t *msrpm01 = svm->msrpm;
int i;
/*
@ -289,15 +290,15 @@ static bool nested_svm_merge_msrpm(struct kvm_vcpu *vcpu)
for (i = 0; i < nested_svm_nr_msrpm_merge_offsets; i++) {
const int p = nested_svm_msrpm_merge_offsets[i];
u32 value;
u64 offset;
nsvm_msrpm_merge_t l1_val;
gpa_t gpa;
offset = svm->nested.ctl.msrpm_base_pa + (p * 4);
gpa = svm->nested.ctl.msrpm_base_pa + (p * sizeof(l1_val));
if (kvm_vcpu_read_guest(vcpu, offset, &value, 4))
if (kvm_vcpu_read_guest(vcpu, gpa, &l1_val, sizeof(l1_val)))
return false;
msrpm02[p] = msrpm01[p] | value;
msrpm02[p] = msrpm01[p] | l1_val;
}
svm->nested.force_msr_bitmap_recalc = false;