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| author | Sean Christopherson <seanjc@google.com> | 2023-07-28 18:15:52 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-08-03 17:16:29 -0700 |
| commit | 2d63699099ac1fad13a0dbf8538faf4127c062e8 (patch) | |
| tree | f42d430a578d4dbe37d48b75c4a5647ec6cbfe99 /arch/x86/include/asm/kvm_host.h | |
| parent | 229725acfaea0dd81f245aec40986dc766de40fa (diff) | |
| download | lwn-2d63699099ac1fad13a0dbf8538faf4127c062e8.tar.gz lwn-2d63699099ac1fad13a0dbf8538faf4127c062e8.zip | |
KVM: x86: Always write vCPU's current TSC offset/ratio in vendor hooks
Drop the @offset and @multiplier params from the kvm_x86_ops hooks for
propagating TSC offsets/multipliers into hardware, and instead have the
vendor implementations pull the information directly from the vCPU
structure. The respective vCPU fields _must_ be written at the same
time in order to maintain consistent state, i.e. it's not random luck
that the value passed in by all callers is grabbed from the vCPU.
Explicitly grabbing the value from the vCPU field in SVM's implementation
in particular will allow for additional cleanup without introducing even
more subtle dependencies. Specifically, SVM can skip the WRMSR if guest
state isn't loaded, i.e. svm_prepare_switch_to_guest() will load the
correct value for the vCPU prior to entering the guest.
This also reconciles KVM's handling of related values that are stored in
the vCPU, as svm_write_tsc_offset() already assumes/requires the caller
to have updated l1_tsc_offset.
Link: https://lore.kernel.org/r/20230729011608.1065019-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/include/asm/kvm_host.h')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 28bd38303d70..dad9331c5270 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1654,8 +1654,8 @@ struct kvm_x86_ops { u64 (*get_l2_tsc_offset)(struct kvm_vcpu *vcpu); u64 (*get_l2_tsc_multiplier)(struct kvm_vcpu *vcpu); - void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset); - void (*write_tsc_multiplier)(struct kvm_vcpu *vcpu, u64 multiplier); + void (*write_tsc_offset)(struct kvm_vcpu *vcpu); + void (*write_tsc_multiplier)(struct kvm_vcpu *vcpu); /* * Retrieve somewhat arbitrary exit information. Intended to |