On 04/01/2023 19:34, Sean Christopherson wrote:
On Tue, Dec 20, 2022, Paul Durrant wrote:
A sunsequent patch will need to acquire the CPUID leaf range for emulated
Xen so explicitly pass the signature of the hypervisor we're interested in
to the new function. Also introduce a new kvm_hypervisor_cpuid structure
so we can neatly store both the base and limit leaf indices.
Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
---
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
v6:
- New in this version
---
arch/x86/include/asm/kvm_host.h | 7 ++++++-
arch/x86/kvm/cpuid.c | 15 ++++++++-------
2 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f35f1ff4427b..ff201ad35551 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -710,6 +710,11 @@ struct kvm_queued_exception {
bool has_payload;
};
+struct kvm_hypervisor_cpuid {
+ u32 base;
+ u32 limit;
+};
Probably makes sense to place this above "struct kvm_vcpu_xen" right away to
avoid the (very minor) churn.
Sure.
struct kvm_vcpu_arch {
/*
* rip and regs accesses must go through
@@ -826,7 +831,7 @@ struct kvm_vcpu_arch {
int cpuid_nent;
struct kvm_cpuid_entry2 *cpuid_entries;
- u32 kvm_cpuid_base;
+ struct kvm_hypervisor_cpuid kvm_cpuid;
u64 reserved_gpa_bits;
int maxphyaddr;
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 0b5bf013fcb8..2468720f8d84 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -180,12 +180,13 @@ static int kvm_cpuid_check_equal(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2
return 0;
}
-static void kvm_update_kvm_cpuid_base(struct kvm_vcpu *vcpu)
+static void kvm_update_hypervisor_cpuid(struct kvm_vcpu *vcpu, const char *hypervisor_signature,
Please wrap. The 80 char limit is a soft limit, but should still be honored unless
there's a good reason to run over.
Ok.
I also vote to name the param "sig" to keep line lengths short.
+ struct kvm_hypervisor_cpuid *hypervisor_cpuid)
Since the struct is a 64-bit value, what about making this a pure getter that
returns a copy?
static struct kvm_hypervisor_cpuid kvm_get_hypervisor_cpuid(struct kvm_vcpu *vcpu,
const char *sig)
{
struct kvm_hypervisor_cpuid cpuid = {};
struct kvm_cpuid_entry2 *entry;
u32 function;
for_each_possible_hypervisor_cpuid_base(cpuid.base) {
entry = kvm_find_cpuid_entry(vcpu, function);
if (entry) {
u32 signature[3];
signature[0] = entry->ebx;
signature[1] = entry->ecx;
signature[2] = entry->edx;
if (!memcmp(signature, sig, sizeof(signature))) {
cpuid.base = function;
cpuid.limit = entry->eax;
break;
}
}
}
return cpuid;
}
vcpu->arch.kvm_cpuid = kvm_get_hypervisor_cpuid(vcpu, KVM_SIGNATURE);
vcpu->arch.xen.cpuid = kvm_get_hypervisor_cpuid(vcpu, XEN_SIGNATURE);
Yes, if that's preferable then no problem.
Paul
