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KVM: arm64: pkvm: Save host FPMR in host cpu context

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Protected KVM stores most of the host's system register state in
kvm_host_data::host_ctxt, which is an instance of struct
kvm_cpu_context. As kvm_cpu_context::sys_regs[] has a slot for FPMR, we
can store the host's FPMR there.

Do so, and remove kvm_host_data::fpmr.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Oliver Upton <oupton@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Mark Rutland
2026-06-03 12:06:15 +01:00
committed by Will Deacon
parent dc23376258
commit da20bb4bc5
3 changed files with 7 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
arch/arm64/include/asm/kvm_host.h
View File

@@ -778,9 +778,6 @@ struct kvm_host_data {
*/
struct cpu_sve_state *sve_state;
/* Used by pKVM only. */
u64 fpmr;
/* Ownership of the FP regs */
enum {
FP_STATE_FREE,

6
arch/arm64/kvm/hyp/include/hyp/switch.h
View File

@@ -554,6 +554,8 @@ static inline void fpsimd_lazy_switch_to_host(struct kvm_vcpu *vcpu)
static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *hctxt = host_data_ptr(host_ctxt);
/*
* Non-protected kvm relies on the host restoring its sve state.
* Protected kvm restores the host's sve state as not to reveal that
@@ -562,11 +564,11 @@ static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
if (system_supports_sve()) {
__hyp_sve_save_host();
} else {
__fpsimd_save_state(host_data_ptr(host_ctxt.fp_regs));
__fpsimd_save_state(&hctxt->fp_regs);
}
if (kvm_has_fpmr(kern_hyp_va(vcpu->kvm)))
*host_data_ptr(fpmr) = read_sysreg_s(SYS_FPMR);
ctxt_sys_reg(hctxt, FPMR) = read_sysreg_s(SYS_FPMR);
}

5
arch/arm64/kvm/hyp/nvhe/hyp-main.c
View File

@@ -66,6 +66,7 @@ static void fpsimd_sve_flush(void)
static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *hctxt = host_data_ptr(host_ctxt);
bool has_fpmr;
if (!guest_owns_fp_regs())
@@ -89,10 +90,10 @@ static void fpsimd_sve_sync(struct kvm_vcpu *vcpu)
if (system_supports_sve())
__hyp_sve_restore_host();
else
__fpsimd_restore_state(host_data_ptr(host_ctxt.fp_regs));
__fpsimd_restore_state(&hctxt->fp_regs);
if (has_fpmr)
write_sysreg_s(*host_data_ptr(fpmr), SYS_FPMR);
write_sysreg_s(ctxt_sys_reg(hctxt, FPMR), SYS_FPMR);
*host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED;
}