diff options
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 81 |
1 files changed, 66 insertions, 15 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 389dfd7594eb..62b0938b62ef 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -38,6 +38,7 @@ #include <linux/file.h> #include <linux/pagemap.h> #include <linux/swap.h> +#include <linux/rwsem.h> #include <asm/apic.h> #include <asm/perf_event.h> @@ -418,11 +419,13 @@ enum { #define VMCB_AVIC_APIC_BAR_MASK 0xFFFFFFFFFF000ULL -static DEFINE_MUTEX(sev_deactivate_lock); +static int sev_flush_asids(void); +static DECLARE_RWSEM(sev_deactivate_lock); static DEFINE_MUTEX(sev_bitmap_lock); static unsigned int max_sev_asid; static unsigned int min_sev_asid; static unsigned long *sev_asid_bitmap; +static unsigned long *sev_reclaim_asid_bitmap; #define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT) struct enc_region { @@ -1231,11 +1234,15 @@ static __init int sev_hardware_setup(void) /* Minimum ASID value that should be used for SEV guest */ min_sev_asid = cpuid_edx(0x8000001F); - /* Initialize SEV ASID bitmap */ + /* Initialize SEV ASID bitmaps */ sev_asid_bitmap = bitmap_zalloc(max_sev_asid, GFP_KERNEL); if (!sev_asid_bitmap) return 1; + sev_reclaim_asid_bitmap = bitmap_zalloc(max_sev_asid, GFP_KERNEL); + if (!sev_reclaim_asid_bitmap) + return 1; + status = kmalloc(sizeof(*status), GFP_KERNEL); if (!status) return 1; @@ -1414,8 +1421,12 @@ static __exit void svm_hardware_unsetup(void) { int cpu; - if (svm_sev_enabled()) + if (svm_sev_enabled()) { bitmap_free(sev_asid_bitmap); + bitmap_free(sev_reclaim_asid_bitmap); + + sev_flush_asids(); + } for_each_possible_cpu(cpu) svm_cpu_uninit(cpu); @@ -1733,7 +1744,7 @@ static void sev_asid_free(int asid) mutex_lock(&sev_bitmap_lock); pos = asid - 1; - __clear_bit(pos, sev_asid_bitmap); + __set_bit(pos, sev_reclaim_asid_bitmap); for_each_possible_cpu(cpu) { sd = per_cpu(svm_data, cpu); @@ -1758,18 +1769,10 @@ static void sev_unbind_asid(struct kvm *kvm, unsigned int handle) /* deactivate handle */ data->handle = handle; - /* - * Guard against a parallel DEACTIVATE command before the DF_FLUSH - * command has completed. - */ - mutex_lock(&sev_deactivate_lock); - + /* Guard DEACTIVATE against WBINVD/DF_FLUSH used in ASID recycling */ + down_read(&sev_deactivate_lock); sev_guest_deactivate(data, NULL); - - wbinvd_on_all_cpus(); - sev_guest_df_flush(NULL); - - mutex_unlock(&sev_deactivate_lock); + up_read(&sev_deactivate_lock); kfree(data); @@ -6273,8 +6276,51 @@ static int enable_smi_window(struct kvm_vcpu *vcpu) return 0; } +static int sev_flush_asids(void) +{ + int ret, error; + + /* + * DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail, + * so it must be guarded. + */ + down_write(&sev_deactivate_lock); + + wbinvd_on_all_cpus(); + ret = sev_guest_df_flush(&error); + + up_write(&sev_deactivate_lock); + + if (ret) + pr_err("SEV: DF_FLUSH failed, ret=%d, error=%#x\n", ret, error); + + return ret; +} + +/* Must be called with the sev_bitmap_lock held */ +static bool __sev_recycle_asids(void) +{ + int pos; + + /* Check if there are any ASIDs to reclaim before performing a flush */ + pos = find_next_bit(sev_reclaim_asid_bitmap, + max_sev_asid, min_sev_asid - 1); + if (pos >= max_sev_asid) + return false; + + if (sev_flush_asids()) + return false; + + bitmap_xor(sev_asid_bitmap, sev_asid_bitmap, sev_reclaim_asid_bitmap, + max_sev_asid); + bitmap_zero(sev_reclaim_asid_bitmap, max_sev_asid); + + return true; +} + static int sev_asid_new(void) { + bool retry = true; int pos; mutex_lock(&sev_bitmap_lock); @@ -6282,8 +6328,13 @@ static int sev_asid_new(void) /* * SEV-enabled guest must use asid from min_sev_asid to max_sev_asid. */ +again: pos = find_next_zero_bit(sev_asid_bitmap, max_sev_asid, min_sev_asid - 1); if (pos >= max_sev_asid) { + if (retry && __sev_recycle_asids()) { + retry = false; + goto again; + } mutex_unlock(&sev_bitmap_lock); return -EBUSY; } |